KR20220102663A - Photonics systems and methods - Google Patents

Abstract

A system and method for short-wave infrared (SWIR) imaging, a low dark current photodetector and associated circuitry for reducing dark current, and a method for generating image information based on data in the photodetector array are disclosed. A SWIR imaging system comprising: (a) a pulsed illumination source operable to emit radiation pulses toward a target in the SWIR band to produce reflected radiation from the target; (b) an imaging receiver comprising a plurality of Ge PDs operative to control operation of the receiver during an integration time such that the accumulated dark current noise does not exceed the time-independent read noise, and operative to detect the reflected SWIR radiation; .

Description

PHOTONICS SYSTEMS AND METHODS

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on U.S. Patent Application Serial No. 16/662,665, filed on October 24, 2019; U.S. Provisional Patent Application No. 63/075426, filed on September 8, 2020; Priority is claimed based on Provisional Patent Application No. 63/093,945 and U.S. Provisional Patent Application No. 63/094,913, filed on October 22, 2020, both of which are incorporated herein by reference in their entirety.

The present disclosure relates to photonics systems, methods, and computer program products. More specifically, the present disclosure relates to electro-optical devices and lasers used in infrared (IR) photonics.

A photodetector device, such as a photodetector array (also referred to as a "photosensor array"), comprises a plurality of photos each comprising one or more photodiodes for detecting impinging light and a capacitance for storing charge provided by the photodiodes. includes the site. The capacitance may be implemented as a dedicated capacitor and/or using parasitic capacitances of photodiodes, transistors and/or other components of the PS. Hereinafter for the sake of simplicity, the term "photodetector device" is often replaced with the abbreviation "PDD", the term "photodetector array" is often replaced with the abbreviation "PDA", and the term "photodiode" The term is often replaced by the abbreviation “PD”.

The term "photosite" relates to a single sensor element of a sensor array (which is also referred to as "sensel" as a hybrid of the words "sensor" and "cell" or "sensor" and "element"), which Also referred to as "sensor element", "light sensor element", "light detector element", and the like. Below, "Photosite" is often replaced by the abbreviation "PS". Each PS may include one or more PDs (eg, if a color filter array is implemented, PDs detecting light in different parts of the spectrum may optionally be collectively referred to as a single PS). The PS may also include some circuitry or additional components in addition to the PD.

Dark current is a well-known phenomenon, and when referring to PD, it relates to the current flowing through the PD even when no photons enter the device. Dark currents in PD can arise from the random generation of electrons and holes within the depletion region of the PD.

In some cases, there is a need to provide a photosite having a photodiode that is characterized by a relatively high dark current while implementing a capacitor of limited size. In some cases, there is a need to provide a PS having a PD characterized by a relatively high dark current while reducing the influence of the dark current on the output detection signal. In PS, which is characterized by high dark current accumulation, it is necessary to overcome the detrimental effect of dark current on electro-optical systems, and it would be advantageous to overcome this. Hereinafter, for the sake of brevity, the term “electro-optic” may be replaced by the abbreviation “EO”.

Shortwave infrared (SWIR) imaging enables a variety of applications that are difficult to perform using visible light imaging. Applications include electronic board inspection, solar cell inspection, production inspection, gate imaging, identification and sorting, surveillance, anti-counterfeiting, process quality control, and more. Many existing InGaAs-based SWIR imaging systems are expensive to manufacture and currently suffer from limited manufacturing capabilities.

Therefore, it would be advantageous to be able to provide a SWIR imaging system that uses a more cost-effective optical receiver based on a PD that is more easily integrated into peripheral electronic devices.

According to one aspect of the present invention, an active SWIR imaging system is disclosed, which is a pulsed illumination source operative to emit pulses of SWIR radiation towards a target, wherein the pulses of radiation impinge upon the target and are reflected from the target. generating a radiation pulse; an imaging receiver comprising a plurality of germanium (Ge) photodiodes (PD) operative to detect the reflected SWIR radiation, the imaging receiver, for each Ge PD, reflected SWIR radiation impinging on each Ge PD generate a dark current greater than 50 μA/cm², time-dependent dark current noise and time-independent read noise; and a controller operative to control operation of the imaging receiver during an integration time during which the accumulated dark current noise does not exceed the time independent read noise.

According to one aspect of the present invention, a method is disclosed for generating a short-wave infrared (SWIR) image of an object in a field of view (FOV) of an electro-optical system (EO), comprising emitting at least one illumination pulse towards the FOV, generating reflected SWIR radiation from the at least one target; triggering the initiation of continuous signal acquisition by an imaging receiver comprising a plurality of germanium (Ge) photodiodes (PD) operative to detect the reflected SWIR radiation; As a result of triggering, for each Ge PD, at least the charge arising from the collision of the SWIR reflected radiation for each Ge PD, dark current greater than 50 μA/cm², integration-time dependent dark current noise and integration-time independent read noise. collecting; triggering cessation of charge collection when the amount of charge collected as a result of the dark current noise is still lower than the amount of charge collected as a result of the integration-time independent read noise; and generating an image of the FOV based on the charge level collected by each Ge PD.

According to one aspect of the present invention, a shortwave infrared (SWIR) optical system is disclosed, comprising a passive Q-switched laser (also referred to as a “P-QS laser”), which comprises a ceramic neodymium doped yttrium aluminum garnet. a gain medium comprising (Nd:YAG) a gain medium comprising a crystalline (GMC) material; a saturable absorber (SA) rigidly coupled to the gain medium, wherein the SA is a group of doped ceramic materials consisting of trivalent vanadium doped yttrium aluminum garnet (V ³⁺ :YAG) and divalent cobalt doped crystalline material. a saturable absorber (SA) comprising a ceramic saturable absorber crystalline (SAC) material selected from; and an optical cavity in which the gain medium and the saturable absorber are located, the optical cavity comprising an optical cavity comprising a high reflectivity mirror and an output coupler.

For simplicity herein, the term “saturated absorber” is often replaced with the abbreviation “SA”.

According to one aspect of the present invention, a shortwave infrared (SWIR) optical system is disclosed, comprising a P-QS laser, comprising: a gain medium comprising a GMC material comprising ceramic Nd:YAG; an SA rigidly coupled to the gain medium, the SA comprising a ceramic SA crystalline material selected from the group of doped ceramic materials consisting of V ³⁺ :YAG and a divalent cobalt doped crystalline material; and an optical cavity in which the gain medium and the saturable absorber are located, the optical cavity comprising a high reflectivity mirror and an output coupler.

According to one aspect of the present invention, a shortwave infrared (SWIR) optical system is disclosed, comprising a P-QS laser, comprising a ceramic gain medium crystalline (GMC) material comprising rare earth element crystals doped with ceramic neodymium. gain medium; a saturable absorber (SA) rigidly coupled to the gain medium, the SA comprising a ceramic saturable absorber crystalline (SAC) material selected from the group of doped crystalline materials consisting of V ³⁺ :YAG and a cobalt doped crystalline material; ; and an optical cavity in which the gain medium and the SA are located, the optical cavity comprising a high reflectivity mirror and an output coupler.

According to one aspect of the present invention, a method of manufacturing a component for a P-QS laser is disclosed, comprising: inserting at least one first powder into a first mold; compressing the at least one first powder in a first mold to produce a first compact; inserting at least one second powder different from the at least one first powder into a second mold; compressing the at least one second powder in a second mold to produce a second compact; heating the first shaped body to produce a first crystalline material; heating the second shaped body to produce a second crystalline material; and coupling the second crystalline material to the first crystalline material. In this case, one of the first crystalline material and the second crystalline material is a neodymium doped crystalline material, and is a gain medium for a P-QS laser, and the other of the first crystalline material and the second crystalline material is P-QS a saturable absorber (SA) for a laser, selected from the group of a crystalline material consisting of a neodymium doped crystalline material and a doped crystalline material, wherein the doped crystalline material consists of V ³⁺ :YAG and a cobalt doped crystalline material. selected from the group of doped crystalline materials. Also in this case, at least one of the gain medium and the SA is a ceramic crystalline material.

According to one aspect of the present invention, a photodetector device (PDD) is disclosed, comprising: an active photosite (PS) comprising an active photodiode (PD); reference PS including reference PD; a first voltage controlled current circuit configured as a voltage controlled current source or a voltage controlled current sink and coupled to the active PD; and a control voltage generating circuit coupled to the active voltage control current circuit and the reference PS, the voltage level responsive to the dark current of the reference PD to reduce the effect of the dark current of the active PD at the output of the active PS; and a control voltage generating circuit used to provide a control voltage to the voltage controlled current circuit.

According to one aspect of the present invention, a method for reducing the influence of dark current in a photodetector device (PDD) is disclosed, wherein when the PDD is operated at a first temperature, based on the dark current of at least one reference PD of the PDD, a second 1 determining a control voltage; providing a first control voltage to a first voltage controlled current circuit coupled to at least one active PD of an active PS of the PDD, such that the first voltage controlled current circuit imposes a first dark current countering current at the active PS ; generating a first detection current by the active PD in response to a light collision of the active PD and a dark current generated by the active PD occurring at the object in the field of view of the PDD; In response to the first detection current and the first dark current countering current, a first detection signal having a smaller magnitude than the first detection current is output by the active PS to determine the effect of the dark current on the first detection signal compensating; determining a second control voltage based on the dark current of at least one reference PD of the PDD when the PDD operates at a second temperature that is at least 10° C. higher than the first temperature; providing a second control voltage to the first voltage controlled current circuit, causing the first voltage controlled current circuit to impose a second dark current countering current at the active PS; generating a second detection current by the active PD in response to a light collision of the active PD occurring in the object and a dark current generated by the active PD; and in response to the second detection current and the second dark current countering current, outputting a second detection signal smaller in magnitude than the second detection current by the active PS to compensate for the influence of the dark current on the second detection signal includes steps. In this case, the magnitude of the second dark current countering current is at least two times greater than the magnitude of the first dark current countering current.

According to one aspect of the present invention, a method of testing a photodetector device (PDD) is disclosed, which provides a first voltage to a first input of an amplifier of a control voltage generating circuit, wherein a second input of the amplifier comprises a reference PD and coupled to a second current circuit that supplies a current at a determined level in response to an output voltage of the amplifier, causing the amplifier to generate a first control voltage for a first current circuit of a PS of the PDD; reading a first output signal of the PS generated in response to the current generated by the first current circuit; providing a second voltage different from the first voltage to a first input of the amplifier, causing the amplifier to generate a second control voltage for the first current circuit; reading a second output signal of the PS generated in response to the current generated by the first current circuit; and determining a fault condition of a detection path of the PDD based on the first output signal and the second output signal, the detection path including a PS and a readout circuit associated with the PS.

According to one aspect of the present invention, a system for generating an image is disclosed, which receives from a photodetector array (PDA) results of multiple detection of an object comprising a high reflective surface surrounded on all sides by a low reflective surface; The multiple detection result includes first frame information of an object detected by the PDA during a first frame exposure time and second frame information of an object detected by the PDA during a second frame exposure time longer than the first frame exposure time do; process the first frame information based on the first frame exposure time to provide a first image comprising a bright area representing a high reflective surface surrounded by a dark background representing a low reflective surface; and a processor configured to process the second frame information based on the second frame exposure time to provide a second image including a dark background without bright areas.

According to one aspect of the present invention, a method for generating image information based on data of a photo detector array (PDA) is disclosed, which is representative of the light intensity of different portions of a target detected by the PDA during a first frame exposure time. , receiving first frame information of the low reflection target including the high reflection area from the PDA; processing the first frame information based on the first frame exposure time to provide a first image including a bright area surrounded by a dark background; receiving, from the PDA, second frame information of a low reflection target comprising a high reflection area indicating light intensity of a different portion of the target detected by the PDA during a second frame exposure time longer than the first frame exposure time step; and processing the second frame information based on the second frame exposure time to provide a second image including a dark background without a bright area.

According to one aspect of the present invention, a non-transitory computer readable medium for generating image information based on data in a photo detector array (PDA) is disclosed, which, when executed in a processor, is displayed on the PDA during a first frame exposure time. receiving, from the PDA, first frame information of a black target including a white area, representing light intensity of different portions of the target detected by the PDA; processing the first frame information based on the first frame exposure time to provide a first image including a bright area surrounded by a dark background; receiving, from the PDA, second frame information of a black target including a white area, representing light intensity of different parts of the target detected by the PDA during a second frame exposure time longer than the first frame exposure time step; and processing the second frame information based on the second frame exposure time to provide a second image including a dark background without bright areas.

According to one aspect of the present invention, an electro-optical (EO) system having a dynamic photosite (PS) availability evaluation function is disclosed, which is a photodetector array (PDA) comprising a plurality of photosites, each photosite being provided. is operative to output a detection signal in different frames, wherein the detection signal output for a frame by each photosite represents the amount of light impinging on each photosite during each frame; determine for each of the plurality of photosites that the photosites are unavailable based on a first frame exposure time, and subsequently determine that the photosites are usable based on a second frame exposure time that is shorter than the first frame exposure time; , a working availability filtering module; and a processor operative to generate an image based on the frame detection level of the plurality of photosites. wherein the processor (i), when generating the first image based on the first frame detection level, excludes a first detection signal of the filtered photosite determined to be unusable for the first image by the availability filtering module; (ii) after the capture of the first frame detection level, when generating a second image based on the second frame detection level captured by the PDA, the filtered filtered image determined to be usable for the second image by the availability filtering module and a second detection signal of photosite.

According to one aspect of the present invention, a method is disclosed for generating image information based on data of a photo detector array (PDA), each for each of a plurality of photosites (PS) of the PDA during a first frame exposure time. receiving first frame information including a first frame detection level indicating the intensity of light detected by the PS; based on the first frame exposure time, among the plurality of PSs of the PDD, comprising (a) a first group of usable PSs comprising a first PS, a second PS and a third PS, and (b) a fourth PS; identifying a first group of unavailable PSs; generating a first image based on the first frame detection level of the first group of usable PSs and discarding the first frame detection level of the first group of unusable PSs; after receiving the first frame information, determining a second frame exposure time longer than the first frame exposure time; receiving, for each of the plurality of PSs of the PDA, second frame information comprising a second frame detection level indicative of an intensity of light detected by each PS during a second frame exposure time; Based on the second frame exposure time, a second group of usable PSs including the first PS among the plurality of PSs of the PDD, and a second of unavailable PSs including the second PS, the third PS and the fourth PS identifying a group; generating a second image based on the second frame detection level of the second group of usable PSs and discarding the second frame detection level of the second group of unusable PSs; after receiving the second frame information, determining a third frame exposure time longer than the first frame exposure time and shorter than the second frame exposure time; receiving, for each of the plurality of PSs of the PDA, third frame information comprising a third frame detection level indicative of an intensity of light detected by each PS during a third frame exposure time; Based on the third frame exposure time, a third group of usable PSs including the first PS and the second PS among the plurality of PSs of the PDD, and a third of the unavailable PSs including the third PS and the fourth PS identifying a group; discarding the third frame detection level of the third group of unusable PSs, and generating a third image based on the third frame detection level of the third group of usable PSs.

According to one aspect of the present invention, a non-transitory computer readable medium for generating image information based on data in a photo detector array (PDA) is disclosed, which, when executed in a processor, comprises a plurality of photosites (PS) of a PDA. ) receiving first frame information comprising a first frame detection level indicative of an intensity of light detected by each PS during a first frame exposure time for each of ; based on the first frame exposure time, among the plurality of PSs of the PDD, comprising (a) a first group of usable PSs comprising a first PS, a second PS and a third PS, and (b) a fourth PS; identifying a first group of unavailable PSs; generating a first image based on the first frame detection level of the first group of usable PSs and discarding the first frame detection level of the first group of unusable PSs; after receiving the first frame information, determining a second frame exposure time longer than the first frame exposure time; receiving, for each of the plurality of PSs of the PDA, second frame information comprising a second frame detection level indicative of an intensity of light detected by each PS during a second frame exposure time; Based on the second frame exposure time, a second group of usable PSs including the first PS among the plurality of PSs of the PDD, and a second of unavailable PSs including the second PS, the third PS and the fourth PS identifying a group; generating a second image based on the second frame detection level of the second group of usable PSs and discarding the second frame detection level of the second group of unusable PSs; after receiving the second frame information, determining a third frame exposure time longer than the first frame exposure time and shorter than the second frame exposure time; receiving, for each of the plurality of PSs of the PDA, third frame information comprising a third frame detection level indicative of an intensity of light detected by each PS during a third frame exposure time; Based on the third frame exposure time, a third group of usable PSs including the first PS and the second PS among the plurality of PSs of the PDD, and a third of the unavailable PSs including the third PS and the fourth PS identifying a group; and discarding the third frame detection level of the third group of unusable PSs, and generating a third image based on the third frame detection level of the third group of usable PSs.

Non-limiting examples of the embodiments disclosed herein are described below with reference to the drawings appended hereto listed after this paragraph. The same structure, element, or part that appears in more than one figure may be denoted by the same number in all figures in which it appears. The drawings and description are intended to illuminate and clarify the embodiments disclosed herein, and should not be construed as limiting in any way. All drawings show apparatus or flow diagrams according to examples of the invention disclosed herein. From the drawing:
1A, 1B and 1C are schematic block diagrams illustrating an active SWIR imaging system.
2 is an exemplary graph showing the relative magnitude of noise power after different durations of integration time in a SWIR imaging system.
3A, 3B, and 3C show a flowchart and a schematic diagram, respectively, of a method of operating an active SWIR imaging system in accordance with some embodiments.
4A, 4B and 4C show a flowchart and a schematic diagram, respectively, of an exemplary method of operation of an active SWIR imaging system.
5 is a flowchart illustrating a method of generating a SWIR image of an object in the FOV of the EO system.
6 is a schematic functional block diagram illustrating an example of a SWIR optical system.
7A, 7B and 7C are schematic functional block diagrams illustrating an example of a P-QS laser.
8 and 9 are schematic functional diagrams illustrating a SWIR optical system.
10 is a schematic functional block diagram illustrating an example of a SWIR optical system.
11A, 11B and 11C are flow charts illustrating examples of a method for manufacturing a component for a P-QS laser and a conceptual timeline for execution of the method.
12a schematically shows a PS comprising a PD controlled by a voltage controlled current source.
Figure 12b schematically shows a PS comprising a PD controlled by a voltage controlled current source in a "3T" configuration.
13a and 13b show a PDD comprising a PS and circuitry that operates to reduce the effects of dark current.
13C shows a PDD comprising a plurality of PSs and circuits operative to reduce the effects of dark currents.
14 shows an exemplary PD IV curve and possible operating voltages for a PDD.
15 shows a control voltage generating circuit coupled to a plurality of reference photosites.
16a and 16b show a PDD comprising an array of PSs and reference circuits based on a plurality of PDs.
17 and 18 show a PDD each including a PS and a circuit operative to reduce the effects of dark currents.
19 shows a PDD comprising optics, a processor and additional components.
20 is a flow chart illustrating a method for compensating for dark current in a photo detector.
21 is a flow diagram illustrating a method for compensating for dark current in a photo detector.
22 is a flow diagram illustrating a method for testing a photo detector.
23 illustrates an EO system in accordance with some embodiments.
24 shows an example of a method of generating image information based on data of a PDA.
25 and 26 show, respectively, a flowchart illustrating a method for generating a model for PDA operation at different frame exposure times and a graphical representation of the execution of the method for different frames taking the same scene at different frame exposure times.
27 is a flowchart illustrating an example of a method for generating images based on different subsets of PS at different operating conditions.
28A and 28B illustrate an EO system and example target objects.
29 is a flowchart illustrating a method of generating image information based on data of a PDA.
It will be understood that, for simplicity and clarity of illustration, elements shown in the drawings have not necessarily been drawn to scale. For example, the dimensions of some elements may be exaggerated relative to others for clarity. Further, where deemed appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements.

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the disclosure. However, it will be understood by one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail in order not to obscure the present disclosure.

In the drawings and descriptions presented, the same reference numbers indicate components common to different embodiments or configurations.

Unless specifically stated otherwise, "processing", "calculating", "calculating", "determining", "generating", "establishing" The use of terms such as , "comprising", "selecting", "defining", etc. refers to the operation of a computer and/or to manipulate and/or transform data representing physical objects and/or physical quantities, such as electronic quantities, into other data. or process.

The terms “computer,” “processor,” and “controller” are used by way of non-limiting examples, including personal computers, servers, computing systems, communication devices, processors (eg, digital signal processors (DSPs), microcontrollers, field programmable gates). arrays (FPGAs), application specific integrated circuits, etc.), other electronic computing devices, and any combination thereof, should be construed as broadly encompassing all kinds of electronic devices having data processing capabilities.

Operations according to the teachings herein may be performed by a computer specially configured for the desired purpose, or by a general purpose computer specially configured for the desired purpose by means of a computer program stored in a computer-readable storage medium.

As used herein, “for example,” “such as,” “such as,” and variations thereof describe non-limiting embodiments of the invention disclosed herein. In the specification, reference to “in some cases”, “in some cases”, “other instances” or variations thereof means that a particular feature, structure, or characteristic described in connection with the embodiment(s) is in at least one embodiment disclosed herein. means to be included. Accordingly, the expressions “in some cases,” “in some cases,” “in other cases,” or variations thereof do not necessarily refer to the same embodiment(s).

It is understood that certain features of the disclosed subject matter herein, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosed subject matter herein, which are, for brevity, described in the context of a single embodiment, may also be provided individually or in any suitable subcombination.

In embodiments of the invention disclosed herein, one or more steps or steps illustrated in the figures may be executed in a different order, and/or one or more groups of steps may be executed concurrently, and vice versa. The drawings illustrate a general schematic diagram of a system architecture according to an embodiment of the invention disclosed herein. Each module in the figures may be configured with any combination of software, hardware and/or firmware that performs the functions defined and described herein. The modules of the figure may be centralized in one location or distributed in one or more locations.

All references to methods in this specification should apply mutatis mutandis to a system capable of executing the method, and, when executed by a computer, to a non-transitory computer-readable medium storing instructions that enable execution of the method.

All references to a system in this specification shall apply mutatis mutandis to a method that can be executed by the system, and to a non-transitory computer-readable medium storing instructions that can be executed by the system.

References to non-transitory computer readable media or similar terms herein shall apply mutatis mutandis to a system capable of executing instructions stored in the non-transitory computer readable medium, which reads the instructions stored in the non-transitory computer readable medium. It shall apply mutatis mutandis to methods that can be executed by a computer.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The materials, methods, and examples provided herein are illustrative only and not intended to be limiting.

Implementation of the methods and systems of the present disclosure includes performing or completing certain selected tasks or steps manually, automatically, or a combination thereof. Moreover, according to the actual apparatus and equipment of the preferred embodiment of the method and system of the present disclosure, some selected steps may be implemented by hardware or software on any operating system of any firmware or combination thereof. For example, as hardware, selected steps of the present disclosure may be implemented as a chip or circuit. As software, selected steps of the present disclosure may be implemented as a plurality of software instructions executed by a computer using any suitable operating system. In any case, selected steps of the methods and systems of the present disclosure may be described as being performed by a data processor, such as a computing platform, for executing a plurality of instructions.

1A, 1B and 1C are schematic block diagrams illustrating, respectively, active SWIR imaging systems 100, 100' and 100" in accordance with examples of the invention disclosed herein.

As used herein, an “active” imaging system detects light arriving at the system from a field of view (FOV), detects it by an imaging receiver comprising a plurality of PDs, and produces one or more images of the field of view or a portion thereof. to process the detection signal to provide The term "image" means a digital representation of a scene detected by an imaging system, which stores a color value for each picture element (pixel) of the image, and each pixel color is Shows the light reaching the imaging system from different parts of the FOV (0.02° x 0.02° part). Optionally, the imaging system may be further operable to generate another representation of an object or light in a FOV (eg, depth map, 3D model, polygonal mesh), although the term "image" is a two-dimensional (2D) without depth data. refers to the image.

The system 100 includes an illumination source (IS) 102 operative to emit radiation pulses towards one or more targets 104 in the SWIR band, so as to reflect the reflected radiation from the target back in the direction of the system 100 . make it In FIG. 1A , the outgoing light is indicated at 106 and the light reflected towards the system 100 is indicated at 108 . Some of the emitted radiation may also be reflected in other directions, deflected or absorbed by the target. The term "target" means any object in the FOV of the imaging sensor, such as solid, liquid, flexible, and rigid objects. Some non-limiting examples of such objects include vehicles, roads, people, animals, plants, buildings, electronics, clouds, microscopic samples, items in manufacture, and the like. Any suitable type of illumination source 102 may be used, for example, one or more lasers, one or more light emitting diodes (LEDs), one or more incident flashlights, any combination thereof, or the like. As discussed in more detail below, the illumination source 102 may optionally include one or more active lasers, or one or more P-QS lasers.

System 100 also includes at least one imaging receiver (or simply “receiver”) 110 comprising a plurality of germanium (Ge) PDs operative to detect reflected SWIR radiation. The receiver generates for each of the plurality of Ge PDs an electrical signal indicative of the amount of SWIR light impinging within a detectable spectral range. The amount includes the amount of SWIR radiation pulsed light reflected from the target, and may include additional SWIR light (eg, light arriving from the sun or an external light source).

The term "Ge PD" means that the photoinduced excitation of electrons (which can later be detected by photocurrent) is in Ge, in a Ge alloy (eg SiGe), or in a material other than Ge (or Ge alloy) (eg, silicon, SiGe) is associated with any PDs occurring at the interface between them. In particular, the term “Ge PD” relates to both pure Ge PD and Ge-silicon PD. When using a Ge PD containing both Ge and silicon, different concentrations of geranium may be used. For example, the relative fraction of Ge (whether alloyed with or adjacent to silicon) in a Ge PD may range from 5% to 99%. For example, the relative fraction of Ge in Ge PD may be between 15% and 40%. It should be noted that a material other than silicon may also be part of the Ge PD, for example aluminum, nickel, silicide or any other suitable material. In some examples of the present disclosure, the Ge PD may be pure Ge PD (with greater than 99.0% Ge).

It should be noted that the receiver may be implemented as a PDA manufactured on a single chip. Any PD array discussed throughout this disclosure may be used as receiver 110 . The Ge PDs can be arranged in any suitable arrangement, such as a rectangular matrix (straight rows and straight columns of Ge PDs), honeycomb tiling and even irregular configurations. Preferably, the number of Ge PDs in the receiver enables the creation of high resolution images. For example, the number of PDs may be approximately 1 megapixel, 10 megapixel or more in size.

In some embodiments, receiver 110 has the following features:

a. HFOV (Horizontal Field of View) [m]:60

b. WD (working distance) [m]: 150

c. Pixel size[um]:10

d. Resolution (on object) [mm]:58

e. Number of pixels [H]: 1,050

f. Number of pixels [V]: 1112

g. Aspect Ratio:3:1

h. View angle[rad]:0.4

i. Target's reflectance [%]: 10 %

j. Collection (ratio of collected photons to emitted photons, assuming a target reflectance of 100% and assuming Lambertian reflectance):3e ^-9 .

In addition to the colliding SWIR light as discussed above, the electrical signal generated by each of the Ge PDs is also denoted as:

a. A read noise that is random and whose magnitude is independent (or substantially independent) of integration time. Examples of such noise include Nyquist Johnson noise (referred to as thermal noise or kTC noise). The readout process may introduce a DC component to the signal in addition to a statistical component, but the term "read noise" relates to the random component of the signal introduced by the readout process.

b. Dark current noise that is random and accumulates over integration time (ie, integration time dependent). Dark current also introduces a DC component into the signal, in addition to a statistical component (which may or may not be removed, for example, as discussed in relation to FIGS. 12A-22 ), but the term “dark current noise” refers to the dark current It relates to the random component of the signal accumulated over the integration time resulting from .

Some Ge PDs, particularly those combining Ge with other materials (eg, silicon), are characterized by relatively high levels of dark current. For example, the dark current of a Ge PD is greater than 50 µA/cm² (relative to the surface area of the PD), and can even be greater (greater than 100 µA/cm², greater than 200 µA/cm², or greater than 500 µA/cm²). . Depending on the surface area of the PD, this level of dark current can translate to 50 pA or more per Ge PD (eg, 100 pA or more per Ge PD, 200 pA or more per Ge PD, 500 pA or more per Ge PD, or 2 nA or more per Ge PD). PDs of various sizes can be used, such as about 10mm², about 50mm², about 100mm², about 500mm². Note that when Ge PDs are subjected to different levels of non-zero bias (which induces, for example, a dark current greater than 50 pA in each of the plurality of Ge PDs), different magnitudes of dark currents may be generated by the Ge PDs. Should be.

The system 100 further includes a controller 112 and an image processor 114 that control operation of the receiver 110 (and optionally an illumination source (IS) 102 and/or other components). Accordingly, the controller 112 is configured to control the operation of the receiver 110 during a relatively short integration time, thereby limiting the effect of the accumulation of dark current noise on signal quality. For example, the controller 112 may be operative to control the operation of the receiver 110 during the integration time such that the accumulated dark current noise does not exceed the integration time independent read noise.

(대안적으로, y-축을 매칭되는 비선형 다항식 스케일로 그려진 것으로 간주함). 또한, 축은 제로 집적 시간에 서로 교차하지 않다(이 경우, 축적된 암전류 노이즈는 0이다).Reference is now made to FIG. 2 , which is an exemplary graph illustrating the relative magnitude of noise power after different durations of integration time, in accordance with embodiments of the invention disclosed herein. For a given laser pulse energy, the signal-to-noise ratio (SNR) is mostly determined by the noise level, including dark current noise (the noise of dark photocurrent) and thermal noise (this is referred to as kTC noise). As shown in the exemplary graph of FIG. 2 , either dark current noise or thermal noise dominates in affecting the SNR of the electrical signal of the PD, depending on the integration time of the Ge-based receiver 110 . Since the controller 112 limits the operation time of the Ge photodetector for a relatively short period of time (within the range indicated by "A" in FIG. 2), many electrons generated from the dark current noise are not collected, and thus the SNR is improved and the heat Mainly affected by noise. As the receiver integration time increases, noise from the dark current of the Ge photodetector becomes dominant over thermal noise in affecting the receiver SNR, degrading receiver performance. The graph of Figure 2 is illustrative only, and the accumulation of dark current noise over time generally increases with the square root of time:

(Alternatively, consider the y-axis as drawn on a matching nonlinear polynomial scale). Also, the axes do not intersect each other at zero integration time (in this case, the accumulated dark current noise is zero).

Returning to system 100, controller 112 controls the receiver for a shorter integration time (eg, integration time during which accumulated dark current noise does not exceed half the read noise or 1/4 of the read noise). It should be noted that the operation of 110 can be controlled. It should be noted that, unless specifically required, limiting the integration time to a very low level limits the amount of light-guided signal that can be detected and deteriorates the SNR to thermal noise. Thermal noise levels in readout circuitry suitable for reading out noisy signals (which require the acquisition of relatively high signal levels) can introduce non-negligible read noise, which can significantly degrade SNR.

In some examples, a somewhat longer integration time may be applied by the controller 112 (eg, integration time while the accumulated dark current noise does not exceed twice the read noise or x 1.5 of the read noise).

Exemplary embodiments disclosed herein relate to systems and methods for high SNR active SWIR imaging using a receiver comprising a Ge-based PD. A major advantage of Ge receiver technology versus InGaAs technology is its compatibility with CMOS processes, which allows the receiver to be fabricated as part of a CMOS production line. For example, Ge PD can be integrated into CMOS processes by growing a Ge epitaxial layer on a silicon (Si) substrate such as Si photonics. Thus, Ge PDs are more cost-effective than equivalent InGaAs PDs.

To utilize Ge PD, the exemplary system disclosed herein is adapted to overcome the limitations of the relatively high dark current of Ge diodes, typically in the range of ˜50 uA/cm ² . The dark current problem is overcome by using active imaging in which short capture times and high-power laser pulses are coupled.

The utilization of Ge PDs, particularly but not limited to those fabricated using CMOS processes, is a much cheaper solution for uncooled SWIR imaging than InGaAs technology. Unlike many prior art imaging systems, the active imaging system 100 includes a pulsed illumination source having a short illumination duration (eg, less than 1 μS, such as 1-1000 μS) and high peak power. This is due to the disadvantages of these pulsed light sources (e.g., illumination non-uniformity, more complex readout circuitry that can lead to higher levels of read noise) and shorter integration times (e.g. the inability to capture a wide range of distances in a single acquisition cycle). ), several methods are discussed to overcome these shortcomings in order to provide an effective imaging system in the following description.

Reference is now made to FIGS. 1B and 1C , which schematically depict other SWIR imaging systems 100' and 100" in accordance with some embodiments. Like system 100, system 100' includes an active illumination source 102A. ) and receiver 110 . In some embodiments, imaging system 100 , 100 ′ and 100 ″ further includes controller 112 and image processor 114 . In some embodiments, the output processing of the receiver 110 may be performed by the image processor 114, and additionally or alternatively, an external image processor (not shown). Imaging systems 100' and 100" may be variations of imaging system 100. Any component or function discussed in connection with system 100 may be implemented in any system 100' and 100". can, and vice versa.

The controller 112 is a computing device. In some embodiments, the functionality of the controller 112 is provided within the illumination source 102 and the receiver 110 , and the controller 112 is not required as a separate component. In some embodiments, control of imaging systems 100' and 100" is performed by controller 112, illumination source 102 and receiver 110 working together. Additionally or alternatively, in some embodiments , control of imaging systems 100' and 100" may be performed (or supplementally performed) by an external controller, such as vehicle electronic control unit (ECU) 120 (which may belong to the vehicle in which the imaging system is installed). have.

The illumination source 102 is configured to emit light pulses 106 in the infrared (IR) region of the electromagnetic spectrum. More specifically, the light pulses 106 are in the SWIR spectral band that includes wavelengths in the range of approximately 1.3 μm to 3.0 μm.

In some embodiments, as shown for example in FIG. 1B , the illumination source (now labeled 102A) includes a gain medium 122 , a pump 124 , a mirror (not shown) and an active QS element 126A. is an active Q-switched laser (or "active Q-switched" laser). In some embodiments, QS element 126A is a modulator. After electronic or optical pumping of the gain medium 122 by the pump 124 , a light pulse is emitted by active triggering of the QS element 126A.

In some embodiments, for example, as shown in FIG. 1C , illumination source 102P is a P-QS laser including gain medium 122 , pump 124 , mirror (not shown) and SA 126P. to be. SA 126P allows the laser cavity to store optical energy (from pumping of gain medium 122 by pump 124) until a saturation level is reached at SA 126P, after which a "passive QS "Light pulses are emitted. A QS pulsed light detector 128 is coupled to the illumination source 102P to detect the emission of the passive QS pulses. In some embodiments, the QS pulsed photodetector 128 is a Ge PD. The signal from the QS pulsed light detector 128 is used to trigger the receiving process in the receiver 110 , such that the receiver 110 will be operated after a period of time suitable for the target 104 distance to be imaged. The time period is derived as further described below with reference to Figures 3b, 3c, 4b and 4c.

In some embodiments, the laser pulse duration from the illumination source 102 is in the range of 100 ps to 1 microsecond. In some embodiments, the laser pulse energy is in the range of 10 microjoules to 100 millijoules. In some embodiments, the laser pulse duration is about 100 microseconds. In some embodiments, the laser pulse duration ranges from 1 microsecond to 100 milliseconds.

The gain medium 122 is provided in the form of crystals or, alternatively, in the form of ceramics. Non-limiting examples of materials that may be used for gain medium 122 include Nd:YAG, Nd:YVO ₄ , Nd:YLF, Nd:Glass, Nd:GdVO ₄ , Nd:GGG, Nd:KGW, Nd:KYW , Nd:YALO, Nd:YAP, Nd:LSB, Nd:S-FAP, Nd:Cr:GSGG, Nd:Cr:YSGG, Nd:YSAG, Nd:Y2O3, Nd:Sc2O3, Er:Glass, Er:YAG etc. In some embodiments, the doping level of the gain medium may vary based on the need for a particular gain. Non-limiting examples of SA (126P) include Co ²⁺ :MgAl ₂ O ₄ , Co ²⁺ :Spinel, Co ²⁺ :ZnSe and other cobalt doped crystals, V ³⁺ :YAG, doped glass, quantum dots, semiconductor SA mirror (SESAM), Cr4+YAG SA, and the like. Additional ways in which P-QS laser 102P may be implemented are discussed below with respect to FIGS. 6-11 , and any variations discussed with respect to laser 600 are also mutatis mutandis for illumination source 102P can be implemented as

Referring to illumination source 102, it is noted that pulsed lasers with sufficient power and short enough pulses are more difficult and more expensive to achieve than non-pulsed illumination, especially when solar absorption-based eye-safe SWIR radiation is required. should pay attention to

The receiver 110 may include one or more Ge PDs 118 and receiver optics 116 . In some embodiments, receiver 110 includes a 2D array of Ge PDs 118 . The receiver 110 is selected to be sensitive to infrared light, including at least the wavelength transmitted by the illumination source 102 , allowing the receiver to form an image of the illuminated target 104 from the reflected radiation 108 .

The receiver optics 116 collect, focus, and selectively filter the reflected electromagnetic radiation 228 and include one or more optical elements, such as mirrors or lenses, arranged to focus the electromagnetic radiation at a focal plane of the receiver 110 . may include

The receiver 110 generates an electrical signal representative of an image of the illuminated scene in response to the electromagnetic radiation detected by the one or more Ge PDs 118 . The signal detected by the receiver 110 may be transmitted to an internal image processor 114 or an external image processor (not shown) for processing into a SWIR image of the target 104 . In some embodiments, receiver 110 is actuated multiple times to create a “time slice” each comprising a specific distance range. In some embodiments, the image processor 114 may be configured by Gruber, Tobias, et al ["Gated2depth: real-time high-density LIDAR from gated images." arXiv preprint arXiv:1902.04997 (2019), which is incorporated herein by reference in its entirety], combines these slices to create a single image with greater visual depth.

In the automotive sector, the image of the target 104 in the field of view (FOV) of the receiver 110 generated by the imaging system 100' or 100" can be used for various driver assistance and safety functions, such as Forward Collision Warning (FCW). , Lane Departure Warning (LDW), Traffic Sign Recognition (TSR) and related entity detection such as pedestrians or oncoming vehicles. HUD) and displayed to the driver. Additionally or alternatively, the imaging system 100' or 100" may interface to the vehicle ECU 120 to provide an image or video, resulting in low light levels or poor visibility conditions. can enable autonomous driving.

In an active imaging scenario, a light source, such as a laser, is used in conjunction with an array of optical receivers. Because Ge PD operates in the SWIR band, high-power light pulses are possible without exceeding eye-safety regulations. For implementation of automotive scenarios, typical pulse lengths are ˜100 ns, although long pulse durations of up to about 1 microsecond are expected in some embodiments. For eye safety, a peak pulse power of ~300KW is acceptable, but this level is not practically achievable with current laser diodes. Thus, in the current system, high-power pulses are generated by QS lasers. In some embodiments, the laser is a P-QS laser to further reduce cost. In some embodiments, the laser is an active QS.

As used herein, the term “target” refers to any of an imaged entity, object, region or scene. Non-limiting examples of targets in automotive applications include vehicles, pedestrians, physical barriers, or other objects.

In accordance with some embodiments, an active imaging system comprises an illumination source that emits radiation pulses toward a target to generate reflected radiation from the target, wherein the illumination source comprises a QS laser; and a receiver comprising one or more Ge PDs for receiving the reflected radiation. In some embodiments, the illumination source operates in the SWIR spectral band.

In some embodiments, the QS laser is an active QS laser. In some embodiments, the QS laser is a P-QS laser. In some embodiments, the P-QS laser comprises an SA. In some embodiments, SA is Co ²⁺ :MgAl ₂ O ₄ , Co ²⁺ :Spinel, Co ²⁺ :ZnSe and other cobalt doped crystals, V ³⁺ :YAG, doped glass, quantum dots, semiconductor SA mirrors ( SESAM) and Cr4+YAG SA.

In some embodiments, the system further comprises a QS pulse photodetector for detecting a radiation pulse emitted by the P-QS laser. In some embodiments, the receiver is configured to operate for a time sufficient for the radiation pulses to travel to the target and return to the receiver. In some embodiments, the receiver is operated for an integration time during which the dark current power of the Ge PD does not exceed the kTC noise power of the Ge PD.

In some embodiments, the receiver generates an electrical signal in response to reflected radiation received by the Ge PD, wherein the electrical signal represents an image of a target illuminated by a pulse of radiation. In some embodiments, the electrical signal is processed into an image of the target by either an internal image processor or an external image processor. In some embodiments, the image of the target is processed to provide one or more of forward collision warning, lane departure warning, traffic sign recognition, and detection of a pedestrian or oncoming vehicle.

According to a further embodiment, a method of performing active imaging includes emitting light pulses by an illumination source comprising an active QS laser; and after sufficient time for the light pulses to travel to the target and return to the QS laser, operating a receiver comprising the one or more Ge PDs for a limited period of time to receive the reflected light pulses from the target. In some embodiments, the illumination source operates in the short-wave infrared (SWIR) spectral band. In some embodiments, the limited time period is equal to the integration time during which the dark current power of the Ge PD does not exceed the kTC noise power of the Ge PD.

In some embodiments, the receiver generates an electrical signal in response to a reflected light pulse received by the Ge PD, wherein the electrical signal represents an image of a target illuminated by the light pulse. In some embodiments, the electrical signal is processed into an image of the target by either an internal image processor or an external image processor. In some embodiments, the image of the target is processed to provide one or more of forward collision warning, lane departure warning, traffic sign recognition, and detection of a pedestrian or oncoming vehicle.

According to further embodiments, a method of performing active imaging includes pumping a P-QS laser comprising SA to cause emission of a light pulse when the SA is saturated; detecting the emission of the light pulses by a QS pulsed photodetector; and operating a receiver comprising one or more Ge PDs for a limited period of time to receive the reflected light pulses after sufficient time for the light pulses to travel to the target and return to the QS laser based on the detected light pulse emission. includes In some embodiments, the QS laser operates in the short-wave infrared (SWIR) spectral band.

In some embodiments, SA is Co ²⁺ :MgAl ₂ O ₄ , Co ²⁺ :Spinel, Co ²⁺ :ZnSe, other cobalt doped crystals, V ³⁺ :YAG, doped glass, quantum dots, semiconductor SA mirrors ( SESAM) and Cr4+YAG SA. In some embodiments, the limited time period is equal to the integration time during which the dark current power of the Ge PD does not exceed the kTC noise power of the Ge PD.

In some embodiments, the receiver generates an electrical signal in response to a reflected light pulse received by the Ge PD, wherein the electrical signal represents an image of a target illuminated by the light pulse. In some embodiments, the electrical signal is processed into an image of the target by either an internal image processor or an external image processor. In some embodiments, the image of the target is processed to provide one or more of forward collision warning, lane departure warning, traffic sign recognition, and detection of a pedestrian or oncoming vehicle.

Exemplary embodiments relate to systems and methods for high SNR active SWIR imaging using Ge-based PDs. In some embodiments, the imaging system is a gated imaging system. In some embodiments, the pulsed illumination source is an active or P-QS laser.

Reference is now made to FIGS. 3A , 3B and 3C , which respectively show a flowchart and a schematic diagram of a method of operation of an active SWIR imaging system in accordance with some embodiments. The process 300 shown in FIG. 3A is based on the system 100' described with reference to FIG. 1B. In step 302 , the pump 124 of the illumination source 102A is operated to pump the gain medium 122 . In step 304 , the active QS element 126A emits a light pulse in the direction of the target 104 at a distance of D. In step 306 , at time=T, the light pulses impinge on target 104 , generating reflected radiation towards system 100 ′ and receiver 110 . In step 308, after waiting time=T2, the receiver 110 is operated to receive the reflected radiation. The return propagation delay T2 consists of the pulse flight time from the illumination source 102A to the target 104 plus the flight time of the light signal reflected from the target 104 . Thus, T2 is known for target 104 at distance “D” from illumination source 102A and receiver 110 . The operating period Δt of the receiver 110 is determined based on the required depth of field DoV. DoV is given as 2DoV = c * Δt, where c is the speed of light. A typical Δt of 100 ns provides a field of view depth of 15 meters. In step 310, the reflected radiation is received by receiver 110 for a period of Δt. Data received from receiver 110 is processed by image processor 114 (or an external image processor) to generate a received image. Process 300 may be repeated N times in each frame, where a frame is defined as a set of data transmitted from receiver 110 to image processor 114 (or an external image processor). In some embodiments, N is between 1 and 10,000.

Reference is now made to FIGS. 4A , 4B and 4C , which show flow diagrams and schematic diagrams, respectively, of an exemplary method of operation of an active SWIR imaging system in accordance with some embodiments. The process 400 shown in Fig. 4A is based on the system 100" and saturates SA 126P. In step 404, after reaching the saturation level, SA 126P emits a pulse of light in the direction of target 430 at a distance of D. Step 406 , QS pulsed photodetector 128 detects the emitted light pulses. In step 408, at time=T, the light pulses strike target 430 and strike system 100" and receiver 110. It re-generates the reflected radiation towards it. In step 410, after waiting time=T2 after detection of the light pulse emitted by the QS pulse photodetector 128, the receiver 110 is operated to receive the reflected radiation. The return propagation delay T2 includes the flight time of the pulse from the illumination source 102P to the target 430 plus the flight time of the optical signal reflected from the target 430 . Thus, T2 is known for target 430 at distance "D" from illumination source 102P and receiver 110 . The duration of operation of Δt is determined based on the required depth of field (DoV). In step 412, the reflected radiation is received by receiver 110 for a period of Δt. Data received from receiver 110 is processed by image processor 114 (or an external image processor) to generate a received image. Process 400 may be repeated N times in each frame. In some embodiments, N is between 1 and 10,000.

Referring to all imaging systems 100, 100' and 100", any one of these imaging systems may monitor the charge build-up collected by each of the Ge PDs after the integration time to provide a detection signal for the respective PD. It should be noted that it may include readout circuitry to read out.Unlike LIDAR or other depth sensors, the readout process can be run after a concussion of integration time, so it is irreversibly summed after a wide range of signals. .

With reference to all imaging systems 100, 100' and 100", optionally receiver 110 outputs a set of detection signals representative of the charge accumulated by each of a plurality of Ge PDs over an integration time, wherein the set of detection signals represents an image of a target illuminated by at least one SWIR radiation pulse.

With reference to all imaging systems 100, 100' and 100", the imaging system comprises at least one diffractive optical element (DOE) operative to improve illumination uniformity of the light of the pulsed illumination source prior to emitting light toward the target. ) As described above, the high peak power pulsed light source 102 may produce an insufficiently uniform illumination distribution across different portions of the FOV.DOE (not shown) is the high quality of the FOV. It is possible to improve the uniformity of illumination to create an image, as LIDAR systems and other depth sensors generally do not require equivalent illumination uniformity, so for reasons of cost, system complexity, system volume, etc., the DOE factor may not be included. For example, in a LIDAR system, as long as the entire FOV receives sufficient illumination (above the threshold to detect a target at the minimum required distance), some areas of the FOV will have significantly more light density than other portions of the FOV. It does not matter whether it receives or not. If implemented, the DOE of system 100 can be used, for example, to reduce speckle effects. Imaging systems 100, 100' and 100" may also include lenses, mirrors, prisms. It should be noted that other types of optical devices for directing light from the light source 102 to the FOV may be included, such as , waveguides, and the like.

Referring to all imaging systems 100, 100' and 100", controller 112 operates receiver 110 to sequentially display a series of gated images each representing the detection signals of different Ge PDs at different distance ranges. selectively operable to acquire, the image processor is operative to combine the series of images into a single two-dimensional image, for example, a first image may acquire light between 0-50 m, and a second image may be may acquire light between 50-100 m, the third image may acquire light between 100-125 m from the imaging sensor, and the image processor 114 may combine the plurality of 2D images into a single 2D image In this way, instead of using more light pulses and more calculations, each distance range is captured with accumulated dark current noise still less than the readout noise introduced by the readout circuit. A value (eg, a gray scale value) may be determined as a function of each pixel of the gated image (eg, a maximum value or a weighted average of all values).

Referring to all imaging systems 100, 100' and 100", the imaging system is an uncooled Ge-based SWIR that operates to detect a 1 m x 1 m target with a SWIR reflectance of 20% (in the relevant spectral range) at distances greater than 50 m. It may be an imaging system.

With reference to all imaging systems 100, 100' and 100", pulsed illumination source 102 may be a QS laser operable to emit eye-safe laser pulses with pulse energies between 10 millijoules and 100 millijoules. Although not necessarily, the illumination wavelength may be selected to match the solar absorption band (eg, the illumination wavelength may be between 1.3 μm and 1.4 μm).

With reference to all imaging systems 100, 100' and 100", the output signal by each Ge PD used to generate the image may represent a single scalar for each PD. All imaging systems 100, 100', 100 "), each PD can output an accumulated signal representing a wide range. For example, some, most, or all of the Ge PDs of the receiver 110 may output a detection signal representing each light reflected from 20m, 40m, and 60m to the respective PD.

Another differentiating feature of the imaging systems 100, 100' and 100" over many known art systems is that pulsed illumination (unlike photographic flash illumination, for example) helps to freeze the rapid movement of objects in the field. It is not used, and the same is used in static scenes. Another differentiating feature of imaging systems 100, 100' and 100" over many known technology systems is that gating of images is cumbersome for some known techniques (e.g., sunlight) compared to external noise, it is not used to avoid internal noise of the system.

Any of the components, features, modes of operation, system architecture, and internal relationships discussed above with respect to systems 100, 100' and 100" may be any of the EO systems discussed below, e.g., systems 700, 1300. , 1300', 1600, 1600', 1700, 1800, 1900, 2300 and 3600) may be implemented mutatis mutandis.

5 is a flow diagram illustrating a method 500 for generating a SWIR image of an object in the FOV of an EO system according to an example of the invention disclosed herein. Referring to the example described with respect to the previous figures, method 500 may be executed by any one of imaging systems 100, 100', and 100". Method 500 may also include any of the active imaging systems described below. It should be noted that it may be implemented by a system (eg, systems 700, 1300, 1300', 1600, 1600', 1700, 1800, 1900, 2300 and 3600).

Method 500 begins with emitting (or “step”) 510 at least one illumination pulse towards a FOV, causing SWIR radiation to be reflected from at least one target. Hereinafter, "step" and "step" are used interchangeably. Optionally, the one or more pulses may be high peak power pulses. For example, it may be necessary to utilize multiple illumination pulses to achieve a higher overall level of illumination as compared to a single pulse. Referring to the example of the accompanying drawings, step 510 may optionally be performed by the controller 112 .

Step 520 includes triggering the initiation of continuous signal acquisition by an imaging receiver comprising a plurality of Ge PDs (in the sense discussed above with respect to receiver 110) operative to detect reflected SWIR radiation. do. The continuous signal acquisition of step 520 means that the charge is continuously and irreversibly collected, not in small increments (ie, the level of charge collected at the intermediate time is unknown). The triggering of step 520 may be executed prior to step 510 (eg, if the detection array requires a ramp-up time), may be executed concurrently with step 510 , or may be executed concurrently with step 510 , or if step 510 is It can be executed after it is finished (eg, to start detection at a non-zero distance from the system). Referring to the example of the accompanying drawings, step 520 may optionally be performed by the controller 112 .

Step 530 begins after the triggering of step 520, and as a result of the triggering, for each of a plurality of Ge PDs, a charge resulting from the impact of the SWIR reflected radiation, a dark current greater than 50 μA/cm², an integrated time dependent dark current noise and collecting integration time independent read noise. Referring to the example of the accompanying drawings, step 530 may be selectively performed by the receiver 110 .

Step 540 includes triggering cessation of charge collection when the amount of charge collected as a result of the dark current noise is still lower than the amount of charge collected as a result of the integration-time independent read noise. The integration time is the duration of step 530 until step 540 is aborted. Referring to the example of the accompanying drawings, step 540 may optionally be performed by the controller 112 .

Step 560 is executed after step 540 ends and includes generating an image of the FOV based on the charge level collected by each of the plurality of Ge PDs. As described above with respect to imaging systems 100, 100', 100", the image generated in step 560 is a 2D image without depth information. Referring to the examples of the accompanying drawings, step 560 is may optionally be performed by the imaging processor 114 .

Optionally, cessation of collection as a result of step 540 is followed by an optional step 550, which reads out a signal correlated to the amount of charge collected by each of the Ge PDs by a readout circuit; , amplifies the readout signal and provides the amplified signal (optionally after further processing) to an image processor that performs generation of the image in step 560 . Referring to the example of the accompanying figures, step 550 is optionally to a read circuit (not shown above, but may be the same as any read circuit discussed below, such as read circuits 1610, 2318 and 3630). can be performed by It should be noted that step 550 is optional, as any other suitable method of reading the detection result from the Ge PS may be implemented.

Optionally, a signal output by each of the plurality of Ge PDs is a scalar representing the amount of light reflected from 20m, the amount of light reflected from 40m, and the amount of light reflected from 60m.

Optionally, the generating step of step 560 may include generating an image based on the read scalar value for each of the plurality of Ge PDs. Optionally, the emitting step of step 510 comprises passing the pulsed laser illumination (by one or more lasers) through at least one diffractive optical element (DOE) and emitting the diffracted light in a FOV, whereby illumination uniformity of the pulsed laser illumination is achieved. may include increasing sex. Optionally, the dark current is greater than 50 picoamps per Ge PD. Optionally, the Ge PD is a Si-Ge PD comprising both silicon and Ge, respectively. Optionally, the emission is performed by at least one active QS laser. Optionally, the emission is performed by at least one P-QS laser. Optionally, the acquisition is performed when the receiver operates at a temperature of 30° C. or higher, and processes the image of the FOV to detect a plurality of vehicles and a plurality of pedestrians in a plurality of ranges between 50 m and 150 m. Optionally, emitting comprises emitting a plurality of illumination pulses having a pulse energy of between 10 millijoules and 100 millijoules into the unprotected eye of a person at a distance of less than 1 m without damaging the eye.

As described above for active imaging systems 100, 100' and 100", multiple gate images may be combined into a single image. Optionally, method 500 may include multiple sequences of emission, triggering, acquisition, and interruption. repeating times; triggering the acquisition at a different time than emitting light in every sequence, in each sequence, the method 500 is wider than 2 m (e.g., 2.1 m, 5 m, 10 m, 25 m, 50 m, 100 m) reading from the receiver the detection values for each of the Ge PDs corresponding to different distance ranges, in this case generating the image in step 560 from different Ge PDs in different sequences. It involves generating a single two-dimensional image based on the detected values read in. Since only a few images are taken, gated images are not uncommon (i.e., in all or most of them, there are detected values for many pixels). It should also be noted that the gated image may have overlapping distance ranges, for example, the first image may represent the distance range 0-60m, the second image may represent the distance range 50- may represent 100 m, and the third image may represent a distance range of 90-120 m.

2-11C show SWIR electro-optical (EO) systems and P-QS lasers that may be used in such systems, and methods of operation and fabrication of such lasers.

10 is a schematic functional block diagram illustrating an example of a SWIR optical system 700 according to an example of the invention disclosed herein. System 700 includes at least a P-QS laser 600 , but may also include additional components as shown in FIG. 10 , such as:

a. A sensor 702 operative to sense reflected light from the FOV of the system 700 , and in particular the reflected illumination of the laser 600 reflected from an external object 910 . Referring to another example, the sensor 702 may be an imaging receiver, PDA, or light detection device discussed in this disclosure, such as components 110, 1300, 1300', 1600, 1600', 1700, 1800, 1900, 2302 and 3610).

b. A processor (710) operative to process the detection results of the sensor (702). The output of the processing may be an image of the FOV, a depth model of the FOV, a spectroscopic analysis of one or more portions of the FOV, information of an identified object in the FOV, lighting statistics in the FOV, or any other type of output. Referring to other examples, processor 710 may be implemented with any one of the processors discussed in this disclosure, such as processors 114 , 1908 , 2304 and 3620 .

c. A controller 712 operative to control the operation of the laser 600 and/or the processor 710 . For example, controller 712 may include controlling timing, synchronization, and other operating parameters of processor 710 and/or laser 600 . Referring to another example, controller 712 may be implemented with any of the other controllers discussed in this disclosure, such as controllers 112 , 1338 , 2314 and 3640 .

Optionally, system 700 can include a SWIR PDA 706 that is sensitive to the wavelength of the laser. In this way, a SWIR optical system can function as an active SWIR camera, a SWIR time-of-flight (ToF) sensor, a SWIR light detection and range measurement (LIDAR) sensor, and the like. The ToF sensor may be sensitive to the wavelength of the laser. Alternatively, the PDA may be a CMOS based PDA sensitive to the SWIR frequency emitted by the laser 600 , which is a CMOS based PDA designed and manufactured by TriEye LTD., Tel Aviv, Israel.

Optionally, system 700 can include a processor 710 for processing detection data from a SWIR PDA (or any other photosensitive sensor of system 700 ). For example, the processor may process the detection information to provide a SWIR image of the field of view (FOV) of the system 700 , detect objects within the FOV, and the like. Optionally, the SWIR optical system comprises a ToF SWIR sensor sensitive to the wavelength of the laser, and a ToF SWIR sensor operable to synchronize operation of the P-QS SWIR laser with the ToF SWIR sensor to detect a distance from the field of view of the SWIR optical system to the at least one object. It may include a controller. Optionally, system 700 includes a controller 712 operative to control one or more aspects of operation of other components of the system, such as laser 600 or photodetector array (eg, focal plane array, FPA). may include For example, some parameters of a laser that can be controlled by a controller include timing, duration, intensity, focus adjustment, and the like. Although not necessarily, the controller may control the operation of the laser based on the detection result of the PDA (either directly or based on processing by the processor). Optionally, the controller may operate to control a laser pump or other type of light source, thereby affecting operating parameters of the laser. Optionally, the controller is operable to dynamically change the pulse repetition rate. Optionally, the controller is operable to control the dynamic modification of the optical shaping optics, for example to improve the signal-to-noise ratio (SNR) in a particular area of the field of view. Optionally, the controller may be operable to control the illumination module to dynamically change the pulse energy and/or duration (e.g. in the same way possible for other P-QS lasers, such as changing the focus of a pumping laser, etc.) .

Additionally and optionally, system 700 generally provides temperature control (eg, passive temperature control, active temperature control) to control the temperature of the laser or the temperature of one or more components (eg, pump diodes). may include Such temperature control may include, for example, a thermoelectric cooler (TEC), a fan, a heat sink, a resistive heater under a pump diode, and the like.

Additionally and optionally, system 700 may include another laser used to bleach at least one of GM 602 and SA 604 . Optionally, system 700 may include an internal photosensitive detector (eg, one or more PDs such as PDA 706), which pulses laser 600 (eg, PD (eg, as described above) 226))). In such a case, the controller 740 sends a triggering signal based on the timing information obtained from the internal photosensitive detector 706 to the PDA 706 (or other tangible camera or sensor 702).

The major industry requiring high-volume lasers in the aforementioned spectral range (1.3-1.5 μm) is the electronics industry for optical data storage, which has lowered the cost of diode lasers to less than a few dollars per watt, per device. However, these lasers require lasers with fairly large peak power and beam brightness and are not suitable for other industries such as the automotive industry where they are utilized in harsh environmental conditions.

It should be noted that there is no scientific consensus on the range of wavelengths considered to be part of the SWIR spectrum. Nevertheless, for purposes of this disclosure, the SWIR spectrum includes electromagnetic radiation at wavelengths longer than the visible spectrum and including at least the spectral range between 1,300 and 1,500 nm.

Although not limited to this use, one or more P-QS lasers 600 may be used as the illumination source 102 of any one of the imaging systems 100, 100' and 100". The laser 600 may be a light radar. It can be used in any other EO system operating in the SWIR range that requires pulsed illumination, such as (lidar), spectroscopy, communication systems, etc. The proposed laser 600 and method of manufacturing such a laser can be achieved at a relatively low cost of production. It should be noted that it enables the high-volume fabrication of lasers operating in the SWIR spectral range.

The P-QS laser 600 includes at least one crystalline gain medium 602 (hereinafter the gain medium is also referred to as “GM”), a crystalline SA 604 , and an optical cavity 606 in which the aforementioned crystalline material is confined/constrained. ), thereby allowing light propagating within the gain medium 602 to be enhanced toward generating a laser light beam 612 (eg, illustrated in FIG. 8 ). The optical cavity is also known by the terms “optical resonator” and “resonant cavity,” and it includes a high reflectivity mirror 608 (also referred to as a “high reflector”) and an output coupler 610 . Several unique and novel combinations of different types of crystalline materials are discussed below, which allow the fabrication of affordable lasers in large volumes for the SWIR spectral range using various fabrication techniques for laser fabrication. General details generally known in the art with respect to P-QS lasers are not provided herein for reasons of brevity of the present disclosure, but are readily available from a variety of resources. The saturating absorber of the laser acts as a Q-switch for the laser, as is known in the art. The term “crystalline material” broadly includes any material that is in monocrystalline form or polycrystalline form.

The dimensions of the coupled crystalline gain medium and crystalline SA may vary depending on the purpose for which the particular P-QS laser 600 is designed. In a non-limiting example, the coupled length of SA and GM is 5-15 mm. In a non-limiting example, the coupled length of SA and GM is 2-40 mm. In a non-limiting example, the diameters of SA and GM combinations (eg, circular cylinders or confined within an imaginary cylinder) are between 2-5 mm. In a non-limiting example, the diameter of the SA and GM bond is between 0.5-10 mm.

The P-QS laser 600 includes a gain medium crystalline material (GMC) that is rigidly coupled to a SA crystalline material (SAC). Robust bonding can be implemented by any of the methods known in the art, such as adhesives, diffusion bonding, complex crystal bonding, growing one over the other, and the like. However, as will be discussed below, the robust connection of crystalline materials in the form of ceramics can be achieved using simple and inexpensive means. The GMC and SAC materials may be directly and rigidly connected to each other, but alternatively may be rigidly connected to each other via an intermediate body (eg, another crystal). In some examples, both the gain medium and the SA may be formed by doping different portions of the single piece crystalline material with different dopants (see, eg, those discussed below with respect to SAC materials and GMC materials), or single piece crystalline materials. By co-doping, by doping the same volume of crystalline material with two dopants (eg, ceramic YAG co-doped with N ³⁺ and V ³⁺ ), it can be implemented on a single piece crystalline material. Optionally, the gain medium may be grown on a single crystal saturated absorbent substrate (eg, using liquid phase epitaxial method (LPE)). Note that separate GMC materials and SA crystalline materials are discussed extensively in the disclosure below, and a single piece of ceramic crystalline material doped with two dopants may also be used in any of the following examples as desired. Should be.

7A, 7B and 7C are schematic functional block diagrams illustrating an example of a P-QS laser 600 according to the invention disclosed herein. In FIG. 7A , the two dopants are embodied in two portions of the common crystalline material 614 (acting as both GM and SA), whereas in FIG. 7B , the two dopants are incorporated in a common volume of the common crystalline material 614 ( In the case shown - the common decision as a whole), they are implemented interchangeably. Optionally, GM and SA may be embodied in a single piece crystalline material doped with neodymium and at least one other material. Optionally (eg, as illustrated in FIG. 7C ), either or both of output coupler 610 and high reflectivity mirror 608 are formed of a crystalline material (eg, GM or SA, or a combination of both). crystal) can be directly adhered to one of the

At least one of SAC and GMC is a ceramic crystalline material that is a related crystalline material (eg, doped yttrium aluminum garnet, YAG, doped vanadium) in ceramic form (eg, polycrystalline form). The use of one (and in particular both) of the crystalline material in the form of ceramics allows production in greater numbers and at lower cost. For example, instead of growing discrete monocrystalline materials in a slow and limited process, polycrystalline materials can be made by powder sintering (i.e., compacting and heating the powder to form a solid mass), low temperature sintering, vacuum sintering, etc. can One of the crystalline materials (SAC or GMC) can be sintered over the other, eliminating the need for complex and costly processes such as polishing, diffusion bonding or surface active bonding. Optionally, at least one of GMC and SAC is polycrystalline. Optionally, both GMC and SAC are polycrystalline.

Referring to combinations of crystalline materials from which GMC and SAC may be prepared, such combinations may include:

a. GMC is ceramic neodymium doped yttrium aluminum garnet (Nd:YAG) and SAC is (a) ceramic trivalent vanadium doped yttrium aluminum garnet (V ³⁺ :YAG) or (b) ceramic cobalt doped crystalline material. Optionally, the ceramic cobalt doped crystalline material may be a divalent ceramic cobalt doped crystalline material. In this alternative, both Nd:YAG and SAC selected from the aforementioned group are in ceramic form. A cobalt-doped crystalline material is a crystalline material doped with cobalt. Examples include cobalt-doped spinel (Co:Spinel or Co ²⁺ :MgAl2, O4) cobalt-doped zinc selenide (Co ²⁺ :ZnSe), and cobalt-doped YAG (Co ²⁺ :YAG). Although not necessarily, in this option the high reflectivity mirror and SA can optionally be rigidly coupled to the gain medium and SA, so that the P-QS laser is a monolithic microchip P-QS laser (e.g., in Figures 8 and 10). exemplified).

b. GMC is a ceramic neodymium doped yttrium aluminum garnet (Nd:YAG), and SAC is a non-ceramic SAC selected from the group of doped ceramic materials consisting of: (a) trivalent vanadium doped yttrium aluminum garnet (V ³⁺ :YAG) )) and (b) cobalt doped crystalline material. Optionally, the cobalt doped crystalline material may be a divalent cobalt doped crystalline material. In this case, the high reflectivity mirror 608 and output coupler 610 are rigidly coupled to the gain medium and SA, so that the P-QS laser 600 becomes a monolithic microchip P-QS laser.

c. GMC is a ceramic neodymium doped rare earth element crystalline material, and SAC is a ceramic crystalline material selected from the group of doped crystalline materials consisting of: (a) trivalent vanadium doped yttrium aluminum garnet (V ³⁺ :YAG) and (b) ) cobalt doped crystalline material. Optionally, the cobalt doped crystalline material may be a divalent cobalt doped crystalline material. Although not necessarily, in this option the high reflectivity mirror 608 and output coupler 610 are optionally rigidly coupled to the gain medium and SA so that the P-QS laser 600 is a monolithic microchip P-QS laser. becomes

It should be noted that in any one of the embodiments, the doped crystalline material may be doped with one or more dopants. For example, the SAC may be doped with the primary dopant disclosed above and at least one other doping material (eg, in significantly lesser amounts). A neodymium doped rare earth element crystalline material is a rare earth element in which the unit cell contains a rare earth element (one of a well-defined group of 15 chemical elements including 15 lanthanide elements, scandium and yttrium), and in a portion of the unit cell the rare earth element It is a crystalline material doped with neodymium (eg, triple ionized neodymium) that replaces the Some non-limiting examples of neodymium doped rare earth element crystalline materials that may be used in this disclosure are:

a. Nd:YAG (as mentioned above), neodymium doped yttrium potassium tungstate (Nd:KYW), neodymium doped yttrium lithium fluoride (Nd:YLF), neodymium doped yttrium orthovanadate (YVO ₄ ), these In all, the rare earth elements are neodymium, Nd;

b. Neodymium doped gadolinium orthovanadate (Nd:GdVO ₄ ), neodymium doped gadolinium gallium garnet (Nd:GGG), neodymium doped potassium-gadolinium tungstate (Nd:KGW), in all of which the rare earth elements are gadolinium, Gd;

c. neodymium doped lanthanum scandium borate (Nd:LSB) in which the rare earth element is scandium;

d. Other neodymium doped rare earth element crystalline materials may be used, wherein the rare earth element may be yttrium, gadolinium, scandium or other rare earth elements.

The following discussion applies to any optional combination of GMC and SAC.

Optionally, the GMC is rigidly coupled directly to the SAC. Alternatively, GMC and SAC may be linked indirectly (eg, SAC and GMC each linked via one or more groups of intermediate crystalline materials and/or via one or more other solid materials transparent to the relevant wavelength). Optionally, one or both of the SAC and the GMC are transparent to the relevant wavelength.

Optionally, the SAC may be a cobalt doped spinel (Co Co ²⁺ :MgAl ₂ O ₄ ). Optionally, the SAC may be cobalt doped YAG (Co:YAG). Optionally, this may enable simultaneous doping of cobalt and neodymium Nd in the same YAG. Optionally, the SAC may be cobalt doped zinc selenide (Co ²⁺ :ZnSe). Optionally, the GMC may be a ceramic cobalt doped crystalline material.

Optionally, the initial transmission (T ) of the SA is between 75% and 90%. Optionally, the initial permeation of SA is between 78% and 82%.

The wavelength emitted by the laser depends on the material used in its construction, particularly the materials and dopants of GMC and SAC. Some examples of output wavelengths include wavelengths in the range of 1,300 nm to 1,500 nm. Some more specific examples include 1.32 μm or about 1.32 μm (eg, 1.32 μm±3 nm), 1.34 μm or about 1.34 μm (eg, 1.34 μm±3 nm), 1.44 μm or about 1.44 μm (eg, 1.44 μm±3 nm). include A corresponding imager sensitive to one or more of these optical frequency ranges may be included in the SWIR optical system 700 (eg, as illustrated in FIG. 10 ).

8 and 9 are schematic functional diagrams illustrating a SWIR optical system 700 according to examples of the invention disclosed herein. As illustrated in these figures, laser 600 may include additional components in addition to those discussed above, including (but not limited to) the following.

a. A light source, such as a flash lamp 616 or laser diode 618 that acts as a pump for the laser. Referring to the previous examples, the light source may serve as the pump 124 .

b. A focusing optics 620 (eg, a lens) for focusing light from a light source (eg, 618 ) onto an optical axis of the laser 600 .

c. A diffuser or other optical device 622 for manipulating the laser beam 612 after the laser beam 612 exits the optical cavity 606 .

Optionally, SWIR optical system 700 may include optics 708 that spread the laser over a wider field of view to improve eye safety issues in the field of view. Optionally, the SWIR optical system 700 may include an optical device 704 that collects the reflected laser light from the FOV and directs it to a sensor 702 , such as a photo detector array (PDA) 706 . can be (see FIG. 10). Optionally, the P-QS laser 600 is a diode pumped solid state laser (DPSSL).

Optionally, the P-QS laser 600 includes at least one diode pump light source 872 and an optical device 620 for focusing the light of the diode pump light source into an optical resonator (optical cavity). Optionally, the light source is positioned on the optical axis (as an end pump). Optionally, the light source may be rigidly coupled to a high reflectivity mirror 608 or SA 604 such that the light source is part of a monolithic microchip P-QS laser. Optionally, the light source of the laser may comprise one or more vertical cavity surface emitting laser (VCSEL) arrays. Optionally, the P-QS laser 600 includes at least one VCSEL array and an optical device for focusing the light of the VCSEL array into an optical resonator. The wavelength emitted by a light source (eg, a laser pump) may vary depending on the crystalline material and/or dopant used in the laser. Some exemplary pumping wavelengths that may be emitted by the pump include 808 nm or about 808 nm, 869 nm or about 869 nm, about 900 nm and some nm.

The power of a laser can vary depending on the application for which it is designed. For example, the laser output power may be between 1W and 5W. For example, the laser output power may be between 5W and 15W. For example, the laser output power may be between 15W and 50W. For example, the laser output power may be between 50W and 200W. For example, the laser output power may be higher than 200W.

QS laser 600 is a pulsed laser and may have different frequencies (repetition rates), different pulse energies, and different pulse durations, depending on the application for which it is designed. For example, the repetition rate of the laser may be between 10 Hz and 50 Hz. For example, the repetition rate of the laser may be between 50 Hz and 150 Hz. For example, the pulse energy of the laser may be between 0.1 mJ and 1 mJ. For example, the pulse energy of the laser may be between 1 mJ and 2 mJ. For example, the pulse energy of the laser may be between 2 mJ and 5 mJ. For example, the pulse energy of the laser may be higher than 5 mJ. For example, the pulse duration of the laser may be between 10 ns and 100 ns. For example, the pulse duration of the laser may be between 0.1 μs and 100 μs. For example, the pulse duration of a laser can be between 100 μs and 1 ms. The size of the laser may be changed, for example, depending on the size of the component. For example, the laser dimensions may be X₁x X₂x X₃, where each dimension (X ₁ , X₂ and X₃) is between 10 mm and 100 mm, between 20 and 200 mm, and so on. The output coupling mirror can be flat, curved, or slightly curved.

Optionally, the laser 600 may further include undoped YAG in addition to the gain medium and SA to prevent heat build-up in the absorption region of the gain medium. The undoped YAG may optionally be shaped into a cylinder (eg, a concentric cylinder) surrounding the gain medium and the SA.

11A is a flow diagram illustrating an example of a method 1100 in accordance with the invention disclosed herein. Method 1100 is a method of manufacturing a component for a P-QS laser, such as, but not limited to, P-QS laser 600 discussed above. Referring to the example presented in relation to the previous drawings, the P-QS laser may be a laser 600 . All of the variations discussed for laser 600 or its components can be implemented for P-QS lasers, where the component is made with method 1100 or its components, and vice versa.

Method 1100 begins with inserting 1102 at least one first powder into a first mold, which is later processed in method 1100 to produce a first crystalline material. The first crystalline material serves as the GM or SA of the P-QS laser. In some examples, the gain medium of the laser is first made (eg, by sintering), and the SA is made later (eg, by sintering) over the previously made GM. In another example, the SA of the laser is built first, and the GM is built later on the previously made SA. In another implementation, SA and GM are made independent of each other and coupled to form a single rigid body. Coupling may be performed as part of heating, sintering, or later.

Step 1104 of method 1100 includes inserting at least one second powder different from at least one first powder into a second mold. The at least one second powder is later processed in method 1100 to produce a second crystalline material. The second crystalline material serves as the GM or SA of the P-QS laser (one of the SA and GM is made from the first crystalline material, the other function is made from the second crystalline material).

The second mold may be different from the first mold. Alternatively, the second mold may be the same as the first mold. In such a case, the at least one second powder can be inserted, for example, on top of the at least one first powder (or on top of the first green body, if already made), next to, around it, and the like. (if implemented) inserting the at least one second powder into the same mold of the at least one first powder may include, prior to treating the at least one first powder into the first compact, the at least one first powder into the first compact. after treatment with the furnace, or sometimes during treatment of the at least one first powder into a first compact.

The first powder and/or the second powder comprises milled YAG (or any of the other aforementioned materials such as spinel, MgAl2, O4, ZnSe) and doping material (eg, N ³⁺ , V ³⁺ , Co ) may be included. The first powder and/or the second powder may comprise YAG (or any of the other aforementioned materials such as spinel, MgAl2, O4, ZnSe) and a doping material (eg N ³⁺ , V ³⁺ , Co). can

Step 1106 is executed after step 1102 and includes compressing at least one first powder in a first mold to produce a first compact. Step 1104 is executed after step 1108, which includes compressing at least one second powder in a second mold to produce a second compact. When the at least one first powder and the at least one second powder are inserted into the same mold in steps 1102 and 1104 , compaction of the powders in steps 1106 and 1108 may be performed simultaneously (eg, at least one presses a second powder of , followed by pressing at least one first powder against a mold), which need not necessarily be the case. For example, step 1104 (and thus step 1108 ) may optionally be executed after the compression of step 1106 .

Step 1110 includes heating the first shaped body to produce a first crystalline material. Step 1112 includes heating the second shaped body to produce a second crystalline material. In other embodiments, heating of the first crystalline may be performed prior to, concurrently with, partially concurrently with, or after each of steps 1106 and 1110 .

Optionally, heating of the first compact in step 1110 is performed prior to (and possibly prior to insertion of) the at least one second powder in step 1108 (and possibly step 1104). . The first shaped body and the second shaped body can be heated separately (eg, for different times, at different temperatures, for different periods of time). The first molded body and the second molded body may be heated together (eg, in the same oven) with or without interconnection during heating. The first molded body and the second molded body may be heated in different heating modes which may share a partial cavity heating, while they may be heated separately in different parts of the heating mode. For example, one or both of the first molded body and the second molded body can be heated separately from the other molded body, and then the two molded bodies can be heated together (eg, after coupling, it need not be so). ). Optionally, the heating of the first shaped body and the heating of the second shaped body comprise simultaneous heating of the first shaped body and the second shaped body in a single oven. Optionally, it is noted that the coupling of step 1114 is the result of simultaneous heating of the two forming bodies in a single oven. Optionally, the coupling of step 1114 is performed by co-sintering both green bodies after they are physically connected to each other.

Step 1116 includes coupling the second crystalline material to the first crystalline material. Coupling may be performed in any manner of coupling known in the art, several non-limiting examples discussed above with respect to P-QS laser 600 . Coupling may have several sub-steps, some of which are closely related to different ones of steps 1106 , 1108 , 1110 and 1112 in different ways in different embodiments. Coupling produces a single rigid crystal containing both GM and SA.

It should be noted that method 1100 may include additional steps used in the preparation of crystals (especially, the preparation of ceramic or non-ceramic polycrystalline crystalline compounds of polycrystalline material coupled to each other). Non-limiting examples include powder manufacturing, binder burnout, densification, annealing, polishing (discussed below, if necessary), and the like.

The GM of the P-QS laser in method 1100 (which may be a first crystalline material or a second crystalline material, as previously mentioned) is a neodymium doped crystalline material. The SA of the P-QS laser in method 1100 (which may be a first crystalline material or a second crystalline material, as previously mentioned) is selected from the group of crystalline materials consisting of: (a) neodymium doped crystalline material and (b) a doped crystalline material selected from the group of doped crystalline materials consisting of trivalent vanadium doped yttrium aluminum garnet (V ³⁺ :YAG) and cobalt doped crystalline material. At least one of GM and SA is a ceramic crystalline material. Optionally, both GM and SA are ceramic crystalline materials. Optionally, at least one of GM and SA is a polycrystalline material. Optionally, both GM and SA are polycrystalline materials.

Although additional steps of the manufacturing process may occur between different steps of method 1100 , it is not necessary in at least some instances to polish the first material prior to bonding of the second material, particularly in the sintering process.

When GMC and SAC refer to combinations of crystalline materials that may be made in method 1100, such combinations may include:

a. GMC is ceramic neodymium doped yttrium aluminum garnet (Nd:YAG) and SAC is (a) ceramic trivalent vanadium doped yttrium aluminum garnet (V ³⁺ :YAG) or (b) ceramic cobalt doped crystalline material. In this alternative, both Nd:YAG and SAC selected from the aforementioned group are in ceramic form. A cobalt-doped crystalline material is a crystalline material doped with cobalt. For example, there are cobalt-doped spinel (Co:Spinel or Co ²⁺ :MgAl ₂ O ₄ ), cobalt-doped zinc selenide (Co ²⁺ :ZnSe). Although not necessarily, this optional high reflectivity mirror and output coupler are optionally rigidly coupled to the GM and SA, making the P-QS laser a monolithic microchip P-QS laser.

b. GMC is a ceramic neodymium doped yttrium aluminum garnet (Nd:YAG), and SAC is a non-ceramic SAC selected from the group of doped ceramic materials consisting of: (a) trivalent vanadium doped yttrium aluminum garnet (V ³⁺ :YAG) )) and (b) cobalt doped crystalline material. In this case, the high reflectivity mirror and output coupler are rigidly connected to the GM and SA, making the P-QS laser a monolithic microchip P-QS laser.

c. GMC is a ceramic neodymium doped rare earth element crystalline material, and SAC is a ceramic crystalline material selected from the group of doped crystalline materials consisting of: (a) trivalent vanadium doped yttrium aluminum garnet (V ³⁺ :YAG) and (b) ) cobalt doped crystalline material. Although not necessarily, this optional high reflectivity mirror and output coupler are optionally rigidly coupled to the GM and SA, making the P-QS laser a monolithic microchip P-QS laser.

Referring throughout method 1100, it should be noted that optionally one or both of SAC and GMC (and optionally one or more intermediately linked crystalline materials) are transparent to the relevant wavelength (eg, SWIR radiation).

11B and 11C include several conceptual timelines for execution of method 1100, in accordance with examples of the invention disclosed herein. To simplify the figure, it is assumed that SA is the result of at least one first powder treatment and that the gain medium is the result of at least one second powder treatment. As mentioned above, roles can change.

12B schematically shows another example of a PS numbered 1200', which is an example of a PS 1200. In PS 1200', another component 1206 is in the form of a "3T" (3-transistor) structure. Any other suitable circuitry may function as the additional component 1206 .

Current source 1204 may be used to provide a current of the same magnitude but in the opposite direction as the dark current generated by PD 1202, thereby canceling (or at least reducing) the dark current. This is particularly useful when PD 1202 is characterized by high dark current. In this way, the charge flowing into the capacitance from the PD (which may be provided by one or more capacitors, the parasitic capacitance of the PS, or a combination thereof, as mentioned above) and the charge due to the dark current can be canceled out. In particular, providing a current by the current source 1204 that is substantially equal in magnitude to the dark current does not cancel the actual electrical signal generated by the PD 1202 as a result of the detected light impinging on the PD 1202 with the provided current. means

13A shows a PDD 1300 according to an example of the invention disclosed herein. PDD 1300 is a circuit capable of controllably matching the current generated by the current source 1204 to the dark current generated by the PD 1202, even when the dark current generated is not constant (changes with time). include It should be noted that the level of dark current generated by PD 1202 may depend on other parameters such as operating temperature and bias applied to the PD (which may also change from time to time).

Reducing the effect of dark current within PS 1200, as performed by PDD 1300 (not a later step in analog or digital signal processing), saturates capacitance or reduces linearity of response to collected charge. Without reducing it, a relatively small capacitance can be utilized.

PDD 1300 includes PS 1200 for sensing impinging light, and a reference PS whose output is used by additional circuitry (discussed below) to reduce or eliminate the effects of dark current in PS 1200 (discussed below). 1310). Similar to PS 1200 (and 1200 ′), reference PS 1310 includes PD 1302 , VCCS 1304 , and optionally additional circuitry (“other components”, collectively denoted 1306 ). . In some examples, the reference PS 1310 of the PDD 1300 may be the same as the PS 1200 of the PDD 1300 . Optionally, any one or more components of PS 1310 may be identical to corresponding components of PS 1200 . For example, PD 1302 may be substantially the same as PD 1202 . For example, VCCS 1304 may be the same as VCCS 1204 . Optionally, any one or more components of PS 1310 may be different from components of PS 1200 (eg, PDs, current sources, additional circuitry). It should be noted that substantially identical components of PS 1200 and PS 1310 (eg, PDs, current sources, additional circuits) may be operated under different operating conditions. For example, different biases may be applied to PDs 1202 and 1302 . For example, different components of additional components 1206 and 1306 may be operated or selectively connected/disconnected using different parameters, even when their structures are substantially the same. For the sake of brevity and clarity, the components of PS 1310 are numbered 1302 (for PD), 1304 (for VCCS), and 1306 (for additional circuitry), although this indicates that such 1204 and 1206).

In some examples, the reference addition circuit 1306 may be omitted or isolated so as not to affect the determination of the dark current. PD 1202 may operate selectively at one of reverse bias, forward bias, zero bias, or between any two or three such biases (eg, such as controller 1338 discussed below). controlled by the controller). PD 1302 may operate selectively at one of reverse bias, forward bias, zero bias, or between any two or three such biases (eg, such as controller 1338 discussed below). controlled by the controller). PDs 1202 and 1302 may, but not necessarily operate under substantially the same bias (eg, about -5V, about 0V, about +0.7V) (eg, as discussed in more detail below). Similarly, when testing PDD 1300). Optionally, a single PS of PDD 1300 may act as PS 1200 (detecting light from the field of view (FOV) of PDD 1300) at some times, while at other times PS 1310 (this The detection signal output of the PDD is used to determine the control voltage for the VCCS of the other PS 1200 of the PDD). Optionally, the roles of the "active" PS and the reference PS used to detect the impinging light can be swapped. The PDD 1300 further includes at least an amplifier 1318 and a control voltage generation circuit 1340 including electrical connections to multiple PSs of the PDD 1300 . Amplifier 1318 has at least two inputs, a first input 1320 and a second input 1322 . A first input 1320 of the amplifier 1318 is supplied with a first input voltage V _FI , which is directly controlled by a controller (PDD 1300 , implemented in an external system, or a combination thereof), or the system can be derived from different voltages of , which in turn can be controlled by the controller. A second input 1322 of amplifier 1318 is coupled to the cathode of PD 1302 (of reference PS 1310 ).

In a first example of use, PD 1202 is held in an operating bias between a first voltage (also referred to as “anode voltage” and denoted as V _A ) and a second voltage (also called “cathode voltage” and denoted as V _C ). do. The anode voltage may be directly controlled by the controller (implemented by PDD 1300, an external system, or a combination thereof), or may be derived from another voltage in the system (which in turn may be controlled by the controller). The cathode voltage may be directly controlled by the controller (implemented by PDD 1300, an external system, or a combination thereof), or may be derived from another voltage in the system (which in turn may be controlled by the controller). Each of the anode voltage V _A and the cathode voltage V _C may or may not be maintained constant over time. For example, the anode voltage V _A may be provided by a constant source (eg, from an external controller via a pad). The cathode voltage V _C may be substantially constant or may vary over time depending on the implementation. For example, when using a 3T structure for PS 1200 , V _C changes over time, for example, due to operation of additional components 1206 and/or current from PD 1202 . V _C may optionally be determined/controlled/affected by an additional component 1206 (not a reference circuit).

VCCS 1204 is used to provide (supply) current to the cathode end of PD 1202 to counteract the dark current generated by PD 1202 . At other times, the VCCS 1204 may supply a different current to achieve the other end (eg, to calibrate or test the PDD 1300 ). The level of current generated by VCCS 1204 is controlled in response to the output voltage of amplifier 1318 . The control voltage for controlling VCCS 1204, denoted V _CTRL , may be equal to the output voltage of amplifier 1318 (as shown). Alternatively, V _CTRL may be derived from the output voltage of amplifier 1318 (eg, due to a resistance or impedance between the output of amplifier 1318 and VCCS 1204 ).

To counteract (or at least reduce) the effect of the dark current of PD 1202 on the output signal of PS 1200 , PDD 1300 is subjected to a bias that PD 1302 is substantially the same as that received by PD 1202 . can do. For example, applying PD 1302 and PD 1202 to the same bias may be used when PD 1302 is substantially equal to PD 1202 . One way to apply the same bias to the two PDs 1202 and 1302 is to apply _a voltage VA to the anode of the PD 1302 (the applied voltage is denoted as V _RPA , RPA denotes the “reference PD anode”) ), applying a voltage V _C to the cathode of the PD 1302 (the applied voltage is denoted as V _RPC , where RPC stands for “reference PD cathode”). Another way to apply the same bias is to apply V _RPA =V _A +ΔV to the anode of PD 1302 and V _RPC =V _C +ΔV to the cathode of PD 1302 . Optionally, the anode voltage V _A , the reference anode voltage V _RPA or both may be provided by an external source (eg, via a printed circuit board (PCB) to which the PDD 1300 is connected).

As mentioned, a first input 1320 of the amplifier 1318 is supplied with a first input voltage V _FI . A second input 1322 of the amplifier 1318 is coupled to the cathode of the PD 1302 . The operation of the amplifier 1318 reduces the voltage difference between its two inputs 1320 and 1322 , directing the voltage of the second input 1322 towards the same control voltage applied to the first input V _FI . . Referring now to FIG. 3B , the dark current (hereinafter referred to as DC _Reference ) through PD 1302 is indicated by arrow 1352 (the circuit shown is the same as the circuit of FIG. 3A ). The current through PD 1302 is equal to the dark current of PD 1202 if PD 1202 is kept in darkness for that time. PDD 1300 (or any system component connected to or adjacent to it) may block light to PD 1302 and thus remain in the dark. Blocking may be by a physical barrier (eg, an opaque barrier), an optical device (eg, a diverting lens), an electronic shutter, or the like. In the description below, it is assumed that all currents on PD 1302 are dark currents generated by PD 1302 . Alternatively, when the PD 1302 receives light (eg, a low level of stray light known in the system), the current source may be implemented to offset the known light originating signal, or the first input voltage V _FI is stray. It can be modified to (at least partially) compensate for (stray) illumination. Barriers, optics, or other dedicated components intended to keep light away from PD 1302 may be implemented at the wafer level (in the same wafer on which PDD 1300 is made), and may be coupled to that wafer (e.g., using adhesive), the wafer can be rigidly connected to the installed casing.

Assuming V _FI is constant (or varies slowly), the output of VCCS 1304 (indicated by arrow 1354 ) must be substantially equal in magnitude to the dark current (DC _Reference ) of PD 1302 , which is ) provides charge carry for dark current consumption of PD 1302, allowing the voltage to be held at V _FI . Because the output of VCCS 1304 is controlled by V _CTRL responsive to the output of amplifier 1318 , amplifier 1318 is output by VCCS 1304 where V _CTRL is equal in magnitude to the dark current through PD 1302 . It is operated to output the required output so that the current can be controlled.

If PD 1202 is substantially identical to PD 1302 and VCCS 1204 is substantially identical to VCCS 1304 , then the output of amplifier 1318 also indicates that VCCS 1204 is identical to the cathode of PD 1202 . It will provide a level of current (DC _Reference ). In this case, in order for the output of the VCCS 1204 to cancel the dark current (hereinafter referred to as DC _ActivePD ) generated by the PD 1202, both the PD 1202 and the PD 1302 generate a dark current of a similar level. that is required To apply the two PDs 1202 and 1302 to the same bias (this causes the two PDs to produce substantially the same level of dark current as the two PDs are maintained at substantially the same condition, e.g., temperature), the amplifier The voltage provided to the first input of 1318 is determined in response to the anode voltage and cathode voltage of PD 1202 and the anode voltage of PD 1302 . For example, if V _A is equal to V _RPA , then V _FI equal to V _C may be provided to the first input 1320 . It should be noted that V _C may vary over time and is not necessarily determined by the controller (eg V _C may be determined as a result of the additional component 1206 ). When PD 1202 is different from PD 1302, and/or when VCCS 1204 is different from VCCS 1304, the output of amplifier 1318 is configured to provide an associated control voltage to VCCS 1204; may be modified by a matching electrical component (not shown) placed between 1318 and VCCS 1204 (eg, where dark current through PD 1202 is linearly correlated with dark current through PD 1302 ). If known, the output of amplifier 1318 can be modified according to a linear correlation. Another way to apply the same bias is to apply V _RPA =V _A +ΔV to the anode of PD 1302, and PD( 1302) is to apply V _{RPC =} V _C +ΔV.

13C illustrates a photodetector device 1300 ′ including a plurality of PSs 1200 according to an example of the invention disclosed herein. PDD 1300' includes all components of PDD 1300 and an additional PS 1200. The other PSs of PDD 1300' are substantially identical to each other (eg, they are all part of a two-dimensional PDA), and thus PDs 1302 of different PSs 1200 produce similar dark currents to each other. Thus, the same control voltage V _CTRL is supplied to all VCCSs 1204 of different PSs 1200 of PDD 1300 ′, such that these VCCSs 1204 cancel out the effect of the dark current generated by each PD 1202 . (or at least reduce). Any of the options discussed above with respect to PDD 1300 may apply mutatis mutandis to PDD 1300 ′.

In some cases (eg, when V _C is not constant, and/or unknown), a first input voltage V _FI selected to generate a similar dark current in PD 1302 as in PD 1202 (eg, , by the controller).

Reference is now made to FIG. 14 , which illustrates an exemplary PD IV curve 1400 according to an example of the invention disclosed herein. For simplicity of explanation, curve 1400 represents the IV curves of both PD 1302 and PD 1202, which for purposes of this description are substantially the same as well as the same anode voltage (i.e., for this description, V _A =V _RPA ). IV curve 1400 is relatively flat between voltages 1402 and 1404, meaning that different biases between 1402 and 1404 applied to the relevant PDs will produce similar levels of dark current. Given _a known VA, the bias on PD 1302 is between voltages 1402 and 1404 when _VC changes within the cathode voltage range which means that the bias on PD 1202 is limited between voltages 1402 and 1404. Applying the V _RPC of the VCCS 1204 causes the VCCS 1204 to output a current sufficiently similar to that of the DC _ActivePD , even if the PD 1202 and PD 1302 are subjected to different biases. In such a case, V _RPC may be within the cathode voltage range, as illustrated by equivalent voltage 1414 , or outside the cathode voltage, as illustrated by equivalent voltage 1412 (but PD 1302 ) still holding bias between 1402 and 1404). As discussed above, modifications or changes to other configurations may be implemented mutatis mutandis. Different biases may be applied to different PDs 1202 and 1302 for different reasons. For example, as part of testing or calibration of a PDA, different biases may be applied.

In real life, different PDs (or other components) of different PSs in a single PDD are not manufactured exactly the same, and the operation of these PSs is not exactly the same as each other. In a PD array, the PDs may be somewhat different from each other and may have slightly different dark currents (eg, due to manufacturing differences, slight differences in temperature, etc.).

15 illustrates a control voltage generation circuit 1340 coupled to a plurality of reference photosites 1310 (collectively designated 1500) in accordance with an example of the invention disclosed herein. The circuit of Figure 15 (also referred to as reference circuit 1500) is for one or more VCCS 1204 of PDDs 1300, 1300' and corresponding one or more PSs 1310 of any PDD variant discussed in this disclosure. It can be used to determine the control voltage (denoted as V _CTRL ). In particular, the reference circuit 1500 may be configured in one or more PSs 1200 of the PDD based on data collected from a plurality of reference PSs 1310 that vary in part (eg, as a result of manufacturing inaccuracies, somewhat different operating conditions, etc.). It can be used to determine the control voltage to counteract (or limit) the effects of dark current. As mentioned earlier, the dark currents of PDs can be different, even if they are similar. In some PD technologies, PDs intended to be identical can be characterized by dark currents that differ by several orders of magnitude, such as x1.5, x2, x4 and more. The averaging mechanism discussed here makes it possible to compensate for even such significant differences (eg, in manufacturing). When an amplifier 1318 is coupled to a plurality of reference PSs 1310 to average the dark current levels of the various PSs 1310, these PSs 1310 can be placed in the dark using, for example, any of the mechanisms discussed above. maintain. The voltages applied to the different VCCSs 1304 of the various PSs 1310 are shorted so that all VCCSs 1304 receive substantially the same control voltage. The cathode voltages of different reference PDs 1302 are shorted to different nets. In this way, although the currents of the different reference PSs 1310 are slightly different from each other (because the reference PS 1310 are slightly different from each other), the average control voltage supplied to one or more PSs 1200 of each PDD (which is also somewhat different from each other) may be different and may be different from the reference PS 1310 ) is accurate enough to cancel out the effect of dark current on the different PS 1200 in a sufficiently uniform manner. Optionally, the output voltage of a single amplifier 1318 is supplied to all PSs 1200 and all reference PSs 1310. Optionally, the PD selected for the PDD has a flat IV response (eg, as discussed above with respect to FIG. 14 ), whereby the PS 1200 differs from the average control voltage discussed with respect to the reference circuit 1500 . It cancels out the dark current to a very good degree. A non-PDD comprising a plurality of reference PSs 1310 in which the average output signal is used to modify the output signal of the plurality of active PSs 1200 (eg, to reduce the effects of dark current on the output signal). A limiting example is provided in FIGS. 16A and 16B . Different configurations, geometries, and numerical ratios may be implemented between the reference PS 1310 and the active PS 1200 of a single PDD. For example, in a rectangular light detection array including a plurality of PSs arranged in rows and columns, an entire row of PS (eg, 1,000 PS) or several rows or columns of PS may be used as the plurality of reference PSs 1310 and (and optionally kept in the dark), the rest of the array receives a control signal based on averaging the outputs of these reference PS rows. This control current generation method greatly reduces the effect of dark current by eliminating the average dark current and leaving only the PS-to-PS transformation.

16A and 16B show a photodetector device comprising a PS array and a reference circuit based on a plurality of PDs according to examples of the invention disclosed herein. PDD 1600 (shown in FIG. 16A ) and PDD 1600 ′ (shown in FIG. 16B , a variant of PDD 1600 ) include all components of PDD 1300 plus additional PS 1200 and PS 1310 ) is included. The different PSs of PDD 1600 (and separately PDD 1600') are substantially equal to each other. Any of the options discussed above with respect to PDDs 1300 and 1300' and circuit 1500 may apply mutatis mutandis to PDDs 1600 and 1600'.

16A shows a photosensitive area 1602 having a plurality of PSs 1200 (array) (which is exposed to external light during operation of the photodetector device 1600), kept in the dark (at least during reference current measurement, optionally at all times). A photodetector device 1600 is shown that includes a region 1604 having a plurality of reference PSs 1310 to be used, and a control voltage generation circuit 1340 further comprising a controller 1338 . The controller 1338 may control the operation of the amplifier 1318 , the voltage supplied to the amplifier 1318 , and/or the operation of the reference PS 1310 . Optionally, controller 1338 may control the operation of PS 1200 and/or other components of PDD 1600 . The controller 1338 can control both the active PS 1200 and the reference PS 1310 under the same operating conditions (eg, bias, exposure time, read regime management). Any functions of the controller 1338 may be implemented by an external controller (eg, may be implemented in another processor of the EO system in which the PDD is installed, or may be implemented by an auxiliary system such as a controller in an autonomous vehicle in which the PDD is installed). can be Optionally, controller 1338 may be implemented as one or more processors fabricated on the same wafer as other components of PDD 1600 (eg, PSs 1200 and 1310 , amplifier 1318 ). Optionally, controller 1338 may be implemented as one or more processors on a PCB coupled to such a wafer. Other suitable controllers may also be implemented as controller 1338 .

16B shows a photo detector device 1600' according to an example of the invention disclosed herein. The photodetector device 1600' is similar to the device 1600, but the components are arranged in different geometries and the internal details of the different PSs are not shown. Also shown is a readout circuit 1610 used to read the detection signals from the PS 1200 and provide them for further processing (eg, noise reduction for image processing), storage, or any other use. have. For example, the read circuitry 1610 may sequentially (perhaps some by one or more processors of the PDD not shown) read the different PS 1200's readings prior to providing it for further processing, storage, or any other operation. after treatment) can be temporarily arranged. Optionally, read circuit 1610 may be implemented as one or more units fabricated on the same wafer as other components of PDD 1600 (eg, PS 1200 and 1310, amplifier 1318). Optionally, the read circuit 1610 may be implemented as one or more units on a PCB connected to such a wafer. Other suitable read circuitry may also be implemented as read circuit 1610 . Read circuitry, such as readout circuitry 1610, may be implemented in any of the light detection devices discussed in this disclosure (eg, PDD 1300, 1700, 1800, and 1900). Examples of analog signal processing that may be performed in the PDD (e.g., by readout circuit 1610 or one or more processors of each PDD) prior to selective digitization of the signal include gain (amplification) correction, offset and binning ( binning, combining output signals from two or more PSs). Digitization of the read data can be implemented on or outside the PDD.

Optionally, PDD 1600 (or any other PDD disclosed herein) samples the output voltage and/or control voltage V _CTRL (if different) of amplifier 1318 , and sets that voltage level to at least a specified It may include a sampling circuit to hold for a minimum period. Such sampling circuitry may be located anywhere (eg, at location 1620 ) between the output of the amplifier 1318 and one or more of the at least one VCCS 1204 . Any suitable sampling circuit may be used. For example, in some cases an exemplary circuit may include a “sample and hold” switch. Optionally, the sampling circuit may be used only some times, other times direct real-time reading of the control voltage is performed. It may be useful to use a sampling circuit, for example, when the magnitude of the dark current in the system changes slowly, when the PS 1310 is shielded from light only a fraction of the time.

17 and 18 show additional light detection devices according to examples of the invention disclosed herein. In the photo detection devices described above (eg, 1300, 1300', 1600, 1600'), a voltage controlled current source was used for both the active PS 1200 and the reference PS 1310 . A current source is an example of a voltage controlled current circuit that may be used in the disclosed PDD. Another type of voltage controlled current circuit that may be used is a voltage controlled current sink, which absorbs a current of a magnitude controlled by the control voltage supplied to it. For example, a current sink may be used in which the bias for PDs 1202 and 1302 is in the opposite direction to the bias illustrated above. More generally, whenever a voltage controlled current source is discussed above ( 1204 and 1304 ), this component may be replaced by a voltage controlled current sink (labeled 1704 and 1714 respectively). It should be noted that using a current sink instead of a current source may require the use of different types of components or circuits in different parts of each PDD. For example, amplifier 1318 used with VCCSs 1204 and 1304 differs in power, size, etc. from amplifier 1718 used with voltage controlled current sinks 1704 and 1714 . To distinguish a PS comprising a voltage controlled current sink rather than a VCCS, reference numerals 1200' and 1310' are used to correspond to PSs 1200 and 1300 discussed above.

In FIG. 17 , PDD 1700 includes a voltage controlled current circuit that is a voltage controlled current sink (in both PS 1200 ′ and PS 1310 ′), and an appropriate amplifier 1718 is used in place of amplifier 1318 . . All of the variations discussed above with respect to current sources apply equally to current sinks.

18, PDD 1800 includes both types of voltage controlled current circuitry, voltage controlled current sources 1204 and 1314 and voltage controlled current sinks 1704 and 1714, along with matching amplifiers 1318 and 1718. do. This allows, for example, the PD of PDD 1800 to operate in forward or reverse bias. At least one switch (or other selection mechanism) may be used to select which reference circuit is enabled/disabled, whether based on VCCS or based on voltage controlled current sink. Such a selection mechanism may be implemented, for example, to prevent two feedback regulators from operating "opposite" to each other (eg, operating at near zero bias for the PD). Any of the options, descriptions, or variations discussed above with respect to any PDD previously discussed (eg, 1300, 1300', 1600, 1600') may apply mutatis mutandis to PDDs 1700 and 1800. In particular, PDDs 1700 and 1800 include a plurality of PSs 1200 ′ and/or a plurality of reference PS 1310 ′ similar to those discussed above (eg, with respect to FIGS. 15 , 16A and 16B ).

In any of the photo-detection devices discussed above, one or more PSs (eg, photo-detection arrays) optionally to a reference PS 1310 (eg, at some time) or to a generic PS 1200 (eg, It should be noted that it can be controlled to be selectively used (at different times). These PSs may contain the circuitry necessary to operate in both roles. For example, if the same PDD is used in different types of electro-optical systems, it may be used. For example, one system may require an averaging accuracy of reference PS 1310 between 1,000 and 4,000, while another system may require a lower averaging accuracy of reference PS 1310 between 1 and 1200. Accuracy may be required. In another example, averaging of control voltages based on some (or all) of PSs may be performed when the entire PDA is darkened and stored in a sample-and-hold circuit as described above, where all PSs are controlled as determined in one or more subsequent frames. It can be used to detect FOV data using voltage.

In the above discussion, for simplicity, it has been assumed that the anode side of every PD on each PDA is coupled to a known (and possibly controlled) voltage, and that the detection signal as well as the connection of the VCCS and additional circuitry as well as the detection signal are implemented on the cathode side. should pay attention to Optionally, it should be noted that PDs 1202 and 1302 can be connected in the opposite direction (such as when the read is on the anode side) as desired.

With reference to all PDDs discussed above (eg, 1300, 1600, 1700, 1800), PS, readout circuitry, reference circuitry, and other aforementioned components (as well as any additional components that may be required) may be used on a single wafer or one It may be implemented on more than one wafer, one or more PCBs or other suitable types of circuitry connected to the PS, and the like.

19 illustrates a PDD 1900 according to an example of the invention disclosed herein. PDD 1900 may implement any combination of features from any one or more of the foregoing PDDs, and may further include additional components. For example, PDD 1900 may include one or more of the following components:

a. At least one light source 1902 operative to emit light in the FOV of the PDD 1900 . Some light from the light source 1902 is reflected from the object in the FOV and is captured by the PS 1200 in the photosensitive area 1602 (exposed to external light during operation of the photodetector device 1900), and the image or object It is used to create other models. Any suitable type of light source may be used (eg, pulsed, continuous, modulated, LED, laser). Optionally, operation of light source 1902 may be controlled by a controller (eg, controller 1338 ).

b. A physical barrier 1904 to keep the area 1604 of the detector array in the dark. The physical barrier 1904 may be part of or outside the detector array. The physical barrier 1904 may be fixed or movable (eg, a moving shutter). It should be noted that other types of darkening mechanisms may also be used. Optionally, the physical barrier 1904 (or other darkening mechanism) may darken different portions of the detection array at different times. Optionally, if changeable, operation of barrier 1904 may be controlled by a controller (eg, controller 1338 ).

c. Ignored Photosites (1906). Not all PSs of the PDA are necessarily used as detection (PS 1200) or reference (PS 1310). For example, some PSs may reside in areas that are not completely dark and not completely bright, and thus are ignored in image generation (or other types of output generated in response to the detection signal of PS 1200 ). Optionally, different PSs may be armed at different times by PDD 1900 .

d. At least one processor (1908) for processing the detection signal output by the PS (1200). Such processing may include, for example, signal processing, image processing, spectroscopic analysis, and the like. Optionally, the results of processing by the processor 1908 may be used to modify the operation of the controller 1338 (or other controller). Optionally, controller 1338 and processor 1908 may be implemented as a single processing unit. Optionally, the results of processing by the processor 1908 may be provided to any one or more of the following: a tangible memory module 1910 (for storage or later retrieval, for future reference), an external system (eg, a remote server or Display 1914 for displaying images or other types of results (eg, graphs, text results from spectrometers) via a communication module 1912, for example, via a vehicle computer in which the PDD 1900 is installed, for example, other types of output interface (eg, speaker, not shown) and the like. Optionally, it should be noted that the signal from PS 1310 may also be processed by processor 1908 to, for example, evaluate the state (eg, operability, temperature) of PDD 1900 . do.

e. A memory module 1910 for storing at least one of a detection signal (eg, if different) output by the active PS or read circuit 1610 and detection information generated by the processor 1908 by processing the detection signal .

f. Power source 1916 (eg, battery, AC power adapter, DC power adapter). The power supply may provide power to the PS, amplifier, or other components of the PDD.

g. Hard casing (1918) (or other type of structural support).

h. An optical device 1920 for directing light from a light source 1902 (if implemented) to the FOV and/or light from the FOV to the active PS 1200 . Such optical devices may include, for example, lenses, mirrors (fixed or movable), prisms, filters, and the like.

As noted above, the aforementioned PDD is configured to match a control voltage that determines the level of current provided by at least one first voltage controlled current circuit (VCCC) 1204 to account for differences in the operating conditions of the PDD. may be used, which alters the level of dark current generated by the at least one PD 1202 . For example, in the case of a PDD comprising a plurality of PSs 1200 and a plurality of PSs 1320: when the PDD operates at a first temperature, the control voltage generation circuit 1340 is applied to the output of the active PS 1200. provide a voltage controlled current circuit with a control voltage for providing a current at a first level in response to the dark current of the plurality of reference PDs 1302 to reduce the influence of the dark current of the active PD 1202 on When the PDD operates at a second temperature (higher than the first temperature), the control voltage generation circuit 1340 is configured to reduce the effect of the dark current of the active PD 1202 on the output of the active PS 1200, In response to the dark current of the reference PD 1302, a control voltage for providing a current at a second level is provided to the voltage controlled current circuit, whereby the second level is greater in magnitude than the first level.

20 is a flow diagram of a method 2000 for compensating for dark current in a photo detector according to an example of the invention disclosed herein. Method 2000 is performed on a PDD comprising at least: (a) a plurality of active PSs, each active PS comprising at least one active PD; (b) at least one reference PS comprising a reference PD; (c) at least one first VCCC coupled to the one or more active PDs; (d) at least one reference VCCC coupled to one or more reference PDs; and (e) a control voltage generation circuit coupled to the active VCCC and the reference VCCC. For example, method 2000 may be practiced on PDDs 1300', 1600, 1600', 1700 and 1800 (the latter two being implementations including multiple active PSs). It should be noted that the method 2000 may include performing any of the operations or functions discussed above with respect to any component of the various PDDs described above.

Method 2000 includes at least steps (steps) 2010 and 1020 . Step 2010 includes generating a control signal based on a level (or levels) of dark current in the at least one reference PD, wherein when provided to the at least one reference VCCC, the at least one reference VCCC Allows to generate a current that reduces the effect of the reference PD's dark current on the output of the reference PS. Step 2020 includes providing a control voltage to the at least one first VCCC, thereby causing the at least one first VCCC to generate a current that reduces the effect of the dark current of the active PD on the output of the plurality of active PSs. . VCCC stands for "voltage controlled current circuit" and is implemented as a voltage controlled current source or voltage controlled current sink.

Optionally, step 2010 is implemented using an amplifier that is part of the control voltage generation circuit. In such a case, step 2010 includes supplying the first input voltage to the first input of the amplifier when the second input of the amplifier is electrically coupled between the reference PD and the reference voltage controlled current circuit. The amplifier may be used to generate a control voltage by continuously reducing the difference between the output of the reference voltage control circuit and the first input voltage. Optionally, both the first VCCC and the reference VCCC are connected to the output of the amplifier.

If the PDD includes a plurality of different reference PDs that generate different levels of dark current, step 2010 may include generating a single control voltage based on the averaging of the different dark currents of the reference PDs.

Method 2000 may include preventing light from the PDD's field of view from reaching the reference PD (eg, using a physical barrier or bypass optics).

Method 2000 may include sampling the output of the active PS after reducing the effect of dark current, and generating an image based on the sampled output.

21 is a flow diagram illustrating a method 1020 for compensating for dark current in a photodetector device according to an example of the invention disclosed herein. Method 1020 has two steps performed in different temperature regions. That is, when the PDD operates at a first temperature T ₁ , the first stage group 1110-1116 is executed, and when the PDD operates at a second temperature T ₂ that is higher than the first temperature, the second Step group 1120-1126 is executed. The difference between the first temperature and the second temperature may be different in different implementations or different instances of the method 1200 . For example, the temperature difference is at least 5 °C; at least 10 °C; at least 20 °C; 40 °C; It may be at least 100° C. or the like. In particular, method 1020 may be effective at smaller temperature differences (eg, less than 1° C.). It should be noted that each of the first temperature and the second temperature may be implemented as a temperature range (eg, 0.1°C; 1°C; 5°C or greater range). All temperatures in the second temperature range are higher than the temperatures in the first temperature range (eg, by the aforementioned ranges). Method 2000 may optionally be executed on any PDD 1300 , 1600 , etc. discussed above. Method 1020 may include performing any of the operations or functions discussed above in connection with any component of the various PDDs described above, wherein the PDD of method 1020 includes any one or more components of the PDD described above. It should be noted that any combination of one or more of the components discussed above with respect to the elements may be included.

Referring to the steps performed when the PDD is operating at a first temperature (which may be a first temperature range), step 2110 includes determining a first control voltage based on the dark current of at least one reference PD of the PDD. include Step 2112 includes providing a first control voltage to a first VCCC coupled to at least one active PD of an active PS of the PDD, causing the first VCCC to impose a first dark current countering current on the active PS do. Step 2114 includes generating a first detection current by the active PD in response to (a) a light collision of the active PD occurring at an object in the PDD's field of view and (b) a dark current generated by the active PD. do. Step 2116 outputs, by the active PS, a first detection signal whose magnitude is smaller than the first detection current, in response to the first detection current and the first dark current countering current, to determine the effect of the dark current on the first detection signal including compensation. The method 1020 also includes an optional step 2118 of generating at least one first image of a FOV of the PDD based on a plurality of first detection signals from a plurality of PSs (and optionally both) of the PDD. may include Step 2118 may be executed when the PDD is at the first temperature, or at a later stage.

Referring to the steps performed when the PDD is operating at a second temperature (which may be in a second temperature range), step 2120 includes determining a second control voltage based on the dark current of at least one reference PD of the PDD. include Step 2122 includes providing a second control voltage to the first VCCC, causing the first VCCC to impose a second dark current countering current on the active PS. Step 2124 includes generating a second detection current by the active PD in response to (a) a light collision of the active PD occurring in the object and (b) a dark current generated by the active PD. Step 2126 outputs, by the active PS, a second detection signal whose magnitude is smaller than the second detection current in response to the second detection current and the second dark current countering current, thereby compensating for the effect of the dark current on the second detection signal includes doing The magnitude of the second dark current countering current may be greater than the magnitude of the first dark current countering current, and may be a ratio greater than one. For example, the ratio may be at least twice or significantly higher (eg, 1, 2, 3- or more-size). Method 1020 also includes an optional step 2128 of generating, based on a plurality of second detection signals from a plurality of PSs (and optionally both) of the PDD, at least one second image of the FOV of the PDD. may include Step 2128 may be executed when the PDD is at the second temperature or at a later stage.

Optionally, the first level of radiation (L ₁ ) from the object impinging the active PD during the first time (t ₁ ) when the first dark current countering current is generated is the second time ( L 1 ) at which the second dark current countering current is generated substantially equal to the second radiation level L ₂ from the object impinging the active PD during t ₂ ), wherein the magnitude of the second detection signal is substantially equal to the magnitude of the first detection signal. Optionally, it should be noted that a PDD according to the present disclosure may be used to detect a signal level that is significantly lower than the level of dark current generated by the PD at a particular operating temperature (eg, 1, 2 or more magnitudes). ). Thus, the method 1020 can be used to issue output signals of similar levels at two different temperatures, where the dark current is at least two times greater than the detection signal and significantly different from each other (eg, x2, x10).

Optionally, determining the first control voltage and determining the second control voltage generates a control voltage comprising at least one amplifier having an input electrically coupled between the reference PD and a reference voltage control current (coupled to the reference PD) implemented by the circuit.

Optionally, the method 1020 may further comprise supplying to another input of the amplifier a first input voltage whose level is determined in response to a bias on the active PD. Optionally, method 1020 may include supplying a first input voltage such that a bias on the reference PD is substantially equal to a bias on the active PD. Optionally, method 1020 may include determining a first control voltage and a second control voltage based on different dark currents of a plurality of reference PDs of the PDD, wherein providing the first control voltage is the same providing a first control voltage to a plurality of first voltage controlled current circuits each coupled to at least one active PD of a plurality of active PDs of the PDD having a different dark current, wherein providing a second control voltage comprises: and providing the same second control voltage to the plurality of first voltage controlled current circuits when the active PDs still have different dark currents.

Optionally, different active PDs generate different levels of dark current at the same time, different reference PDs simultaneously generate different levels of dark current, and the control voltage generating circuit generates the same control voltage based on the averaging of the different dark currents of the second PD. serve to different active PDs. Optionally, method 1020 includes directing light from the field of view to a plurality of active PSs of the PDD using dedicated optics and preventing light from the field of view from reaching a plurality of reference PDs of the PDD can do.

22 is a flow diagram illustrating a method 2200 for testing a light detection device according to an example of the invention disclosed herein. For example, the test may be implemented by any one of the aforementioned PDDs. This means that the sensing paths of different PSs can be tested in real time, further using the same circuit and architecture described above, which is useful for reducing the effects of dark current. Optionally, the test may be performed while the PDD is in an operational mode (ie, not in a test mode). In some examples, some PSs can be tested while exposed to ambient light of the FOV, even when another PS of the same PDD captures a real image of the FOV (with or without compensation for dark current). Nevertheless, it is noted that method 2200 may also optionally be implemented in other types of PDDs. Method 2200 may also optionally be implemented using a circuit or architecture similar to that discussed above with respect to the PDD described above, but when the PD is not characterized by high dark current and reduction of dark current is not required or performed. can be implemented. Although method 2200 is described as being applied to a single PS, it may be applied to some or all PSs of a PDD.

Step 2210 of method 2200 includes providing a first voltage to a first input of an amplifier of a control voltage generating circuit, wherein a second input of the amplifier is controlled according to a reference PD and an output voltage of the amplifier. coupled to a second current circuit for supplying current to the level; This causes the amplifier to generate a first control voltage for the first current circuit of the PS of the PDD. Referring to the example described in connection with the preceding drawings, the amplifier may be an amplifier 1318 or an amplifier 1718, and the PS may be a PS 1310 or a PS 1310'. Examples of first voltages that may be provided to the first input are discussed below.

Step 2220 of method 2200 includes reading a first output signal of the PS generated by the PS in response to a current generated by the first current circuit and a current generated by the PD of the PS.

Step 2230 of method 2200 includes providing a second voltage to a first input of the amplifier that is different from the first input, causing the amplifier to generate a second control voltage for the first current circuit. Examples of such second voltages that may be provided are discussed below.

Step 2240 of the method 2200 includes reading a second output signal of the PS generated by the PS in response to the current generated by the first current circuit and the current generated by the PD of the PS.

Step 2250 of method 2200 includes determining, based on the first output signal and the second output signal, a fault condition of a detection path of the PDD, wherein the detection path includes a PS and a readout circuit associated with the PS. include Examples of what types of faults can be detected while using different combinations of first and second voltages are discussed below.

A first example involves using at least one of a first voltage and a second voltage to attempt to saturate the PS (e.g., regardless of the actual detection level, the capacitance of the PS is greatly affected by the VCCS). by providing high current). Failure to saturate the PS (e.g. receiving a non-white (perhaps completely black or neutral) detection signal) is a problem with the associated PS or additional components of the readout path (e.g. PS amplifiers, samplers, analog-to-digital converters). indicates In this case, the first voltage (eg) causes the amplifier to generate a control voltage, causing the first current circuit to saturate the PS. In such a case, determining the fault condition at step 2250 may include determining that the detection path of the PS is malfunctioning in response to determining that the first output signal is not saturated. The second voltage in this case may be a voltage that does not cause saturation of the PS (eg, the VCCS does not generate a current, only compensates the dark current, preventing the current from being collected by the capacitance). A test as to whether the PS detection path can be saturated can be implemented in real time.

When attempting to saturate one or more PSs to test a PDD, method 2200 may include reading a first output signal while the PS is exposed to ambient light during a first detection frame of the PDD, where a malfunction The determination of the state is performed after predetermining that the detection path is active in response to reading the saturated output signal in the second detection frame earlier than the first frame. For example, during an ongoing operation of the PDD (eg, during video capture), the PS may be determined to be defective or unavailable if a saturation attempt fails after a successful previous time during the same operation. The tests can be run on test frames that are not part of the video or can be run on individual PSs where the saturation output is ignored (e.g., pixel colors corresponding to these PSs can be completed from adjacent pixels of the frame being tested, and these PSs can be treated as unavailable for the duration of this frame).

A second example involves using at least one of a first voltage and a second voltage to attempt to deplete the PS (e.g., irrespective of the actual detection level, which causes the capacitance of the PS to be very high by the VCCS). by providing the opposite current). Failure to deplete the PS (eg, receiving a detection signal that is not black (perhaps completely white or half-tone) indicates a problem with the associated PS or additional components of the readout path. In such a case, the second voltage (eg) causes the amplifier to generate a second control voltage, causing the first current circuit to deplete the detection signal resulting from the viewing light impinging on the PS. In such a case, determining the fault condition at step 2250 may include determining that the detection path is malfunctioning in response to determining that the second output signal is not depleted. The first voltage in this case may be a voltage that does not cause saturation of the PS (eg, the VCCS does not generate a current but only compensates the dark current to saturate the capacitance). A test as to whether the PS detection path can be exhausted can be implemented in real time (eg without darkening each PS).

Upon attempting to deplete one or more PSs to test the PDD, the method 2200 may include reading a second output signal while the PS is exposed to ambient light during a third detection frame of the PDD, where a malfunction The determination of the state is performed after predetermining that the detection path is active in response to reading the exhausted output signal in the fourth sense frame earlier than the third frame.

Another example of using method 2200 of testing a PS using application of multiple control voltages includes applying two or more voltages. For example, three or more different voltages may be provided to the first input of the amplifier at different times (eg, in different frames). In this case, step 2250 may include, based on the first output signal, the second output signal, and at least one other output signal corresponding to the third or higher voltage applied to the first input of the amplifier, the detection path of the PDD. determining a fault condition. For example, three, four or more different voltages may be applied to the first input of the amplifier at different times (e.g., monotonically if all voltages are greater than the previous voltage), corresponding to different voltages. The output signal of the same PS can be tested (eg, the output signal also monotonically increases in magnitude) to correspond to the applied voltage.

An example of using method 2200 to test a portion (or all of it) of a PDD is to send at least two output signals responsive to at least two different voltages provided to amplifiers of each PS to one of a plurality of PSs of the PDD. reading from each, determining an operating state based on at least two output signals output by the at least one PS associated with each first detection path for at least one first detection path, and at least one second detection path and determining the malfunctioning state based on at least two output signals output by at least one other PS associated with each second detection path for the path.

Optionally, method 2200 includes a designated test target (eg, a black target, white target), but this need not be the case.

Optionally, step 2250 may be replaced with determining an operational state of the detection path. This can be used, for example, to correct different PSs of the PDD to the same level. For example, if the PDD is dimmed and there is no dedicated target or dedicated lighting, the same voltage can be applied to the VCCS of different PSs. Different output signals of different PSs may be compared to each other (at one or more different voltages applied to the first input of the amplifier). Based on the comparison, correction values can be assigned to different PS detection paths to provide similar output signals for similar illumination levels (which are simulated by the currents contained by the VCCSs of different PSs). For example, to output a corrected output signal for PS B, it may be determined that the output of PS A must be multiplied by 1.1. For example, to output a corrected output signal for PS D, it may be determined that a delta signal ΔS must be added to the output of PS C. Non-linear corrections may also be implemented.

23 illustrates an EO system 2300 according to an example of the invention disclosed herein. The EO system 2300 includes at least one PDA 2302 and at least one processor 2304 operative to process detection signals from the PS 2306 of the PDA. The EO system 2300 may be any type of EO system that uses a PDA for detection, such as a camera, spectrometer, LIDAR, or the like.

The at least one processor 2304 is configured to operate and process the detection signal output by the PS 2306 of the at least one PDA 2302 . Such processing may include, for example, signal processing, image processing, spectroscopic analysis, and the like. Optionally, the processing result by the processor 2304 may be provided as any one or more of the following: a tangible memory module 2308 (for storage or later retrieval), an external system (eg, a remote server, or the EO system 2300 ) ), a display 2312 for displaying images or other types of results (eg graphs, textual results of a spectrometer), for example via a communication module 2310 , other types of output interfaces (eg, speakers, not shown), and the like.

The EO system 2300 can include a controller 2314 that controls operating parameters of the EO system 2300 (eg, PDA 2302 and optional light source 2316 ). In particular, the controller 2314 may be configured to set (or change) a frame exposure time used for the capture of different frames by the EO system 2300 . Optionally, the processing result of the light detection signal by the processor 2304 may be used to modify the operation of the controller 2314 . Optionally, controller 2314 and processor 2304 may be implemented as a single processing unit.

The EO system 2300 may include at least one light source 2316 operative to emit light into a field of view (FOV) of the EO system 2300 . A portion of the light from the light source 2316 is reflected from the object in the FOV and is captured by the PSs 2306 (at least those PSs located in the photosensitive area exposed to external light during the frame exposure time of the EO system 2300). Detection of light arriving from an object in the FOV (whether it is a reflection of a light source, reflection of another light source, or emitted light) is used to create an image or other model of the object (eg, a three-dimensional depth map). Any suitable type of light source may be used (eg, pulsed, continuous, modulated, LED, laser). Optionally, operation of light source 2316 may be controlled by a controller (eg, controller 2314 ).

The EO system 2300 may include a readout circuit 2318 for reading an electrical detection signal from a different PS 2306 . Optionally, the read circuit 2318 may process the electrical detection signals before providing them to the processor 2304 . Such preprocessing may include, for example, amplification, sampling, weighting, noise removal, correction, digitization, capping, level adjustment, dark current compensation, and the like.

Additionally, the EO system 2300 may include additional components, such as, but not limited to, any one or more of the following optional components.

a. A memory module for storing at least one of a detection signal (eg, otherwise) output by the PS 2306 or read circuit 2318 , and detection information generated by the processor 2304 by processing the detection signal (2308).

b. Power (2320) such as batteries, AC power adapters, DC power adapters, etc. The power source 2320 may provide power to the PDA, read circuitry 2318 , or any other component of the EO system 2300 .

c. Hard casing 2322 (or other type of structural support).

d. An optical device 2324 for directing light from a light source 2316 (if implemented) to the FOV and/or light from the FOV to the PDA 2300 . Such optical devices may include, for example, lenses, mirrors (fixed or movable), prisms, filters, and the like.

Optionally, PDA 2302 can be characterized by a relatively high dark current (eg, as a result of the type and nature of the PD). The capacitance of the individual PS 2306 where the detection charge is collected due to the high level of dark current may be (partially or fully) saturated by the dark current, leaving little or no dynamic range for ambient light detection (reaching from the FOV). have). Dynamic range for detection, although read circuit 2318 or processor 2304 (or any other component of system 2300 ) subtracts the dark current level from the detection signal (eg, to normalize detection data) The lack of , the resulting detection signal of each PS 2306 is oversaturated, insufficient to meaningfully detect the ambient light level. Different PSs with different capacitances because the dark current from the PD of each PS 2306 accumulates in the capacitance (whether the actual capacitor or the parasitic or residual capacitance of other components of the PS) for the entire duration of the frame exposure time (FET). 2306 may become unavailable in other FETs.

24 illustrates an example of a method 2400 for generating image information based on data in a PDA in accordance with the invention disclosed herein. Referring to the example presented in connection with the previous figures, method 2400 may be executed by EO system 2300 (eg, by processor 2304 , controller 2314 , etc.). In such a case, the PDA of method 2400 may optionally be PDA 2302 . Other related components discussed in method 2400 may be corresponding components of EO system 2300 . Method 2400 includes modifying a frame FET (FET) while the PDA collects charge from its PD. This collected charge can arise from intrinsic sources within the detection system, such as the photoelectric response to light impinging on the PD and the PD's dark current. For example, colliding light may arrive from the camera's field of view (FOV) or other EO systems where the PDA is installed. The FET may be controlled electrically, mechanically, by controlling flash illumination duration, etc., or any combination thereof.

It should be noted that the FET may be an entire FET that is the sum of a plurality of distinct durations while the PDA collects charge resulting from photoelectric activity at the PS of the PDA. A full FET is used when the charges collected during different discrete periods are summed to provide a single output signal. This full FET can be used, for example, with pulsed illumination or active illumination where collection is held for a short period of time (eg to avoid being saturated by bright reflections in the FOV). Optionally, it should be noted that a single FET may be used in some frames, while an entire FET may be used in other frames.

Step 2402 of method 2400 includes receiving first frame information. The first frame information includes a first frame detection level indicating the intensity of light detected by each PS during the first FET—for each of the plurality of PSs of the PDA. Receiving the first frame information may, but need not, include receiving a read signal from all PSs of the PDA. For example, some PSs may be defective and not provide a signal. For example, a region of interest (ROI) may be defined for a frame, indicating that data will be collected from only a portion of the frame.

The frame information may be provided in any format, such as a detection level (or levels) for each PS (eg between 0 and 1024, three RGB values, between 0 and 255 each, etc.), scalar, vector, or other format. have. Optionally, the frame information (for the first frame or subsequent frames) may optionally represent a detection signal in an indirect manner (eg, information about the detection level of a given PS with respect to the level of the surrounding PS, or may be provided in relation to the level of the same PS in the previous frame). The frame information may also include additional information (eg, serial number, timestamp, operating conditions), some of which may be used in subsequent steps of method 2400 . The first frame information (or frame information for subsequent frames received at a later stage of method 2400) may be obtained directly from the PDA, or from one or more intermediate units (eg, intermediate processors, memory units, data aggregators, etc.) can be received from The first frame information (or frame information for subsequent frames received at a later stage of method 2400) may include raw data obtained by each PS, but also includes preprocessed data (e.g., weights, denoising, correcting, digitizing, capping, leveling, etc.).

Step 2404 includes identifying at least two types of PS among a plurality of PSs of the PDD based on the first FET:

a. An usable PS group for a first frame comprising at least the first PS, the second PS and the third PS of the PSs of the PDA (referred to as “the first group of usable PSs”).

b. The unusable PS group for the first frame including at least the fourth PS among the PSs of the PDA (referred to as the "first group of unusable PSs").

The identification of step 2404 may be implemented in different ways and may optionally include identifying (explicitly or implicitly) each of the plurality of PSs as belonging to one of the at least two groups described above. Optionally, each PS of the PDA (or a previously determined subgroup, such as all PSs in the ROI) is in one of two pluralities for a first frame (first group of available PSs or first group of unavailable PSs) can be assigned. However, this is not necessarily the case, and some of the PSs may not be allocated for some frames or may be allocated to a plurality of others (e.g., based on parameters other than the FETs of each first frame, for example, a plurality of PSs based on collected data). availability will be determined). Optionally, the identification of step 2404 determines a suitable PS for one of the first plurality of PSs, and automatically assigns the remaining PSs of the PDA (or a predetermined subgroup such as an ROI) as belonging to the other of the plurality of PSs. may include consideration.

It should be noted that the identification of step 2404 (and steps 2412 and 2402) need not reflect the actual usable state of each PS (and in some instances also reflect this actual usable state). . For example, a PS included in the first group of unusable PS is actually usable in the condition of the first frame, whereas another PS included in the first group of available PS may not actually be usable in the condition of the first frame. can The identification of step 2404 is an estimate or evaluation of the PS's usability of the PDA, not a test of each PS. Note that the availability of PS may also be estimated at step 2404 based on other factors. For example, an existing list of defective PSs can be used to exclude those PSs from being considered usable.

The identification of step 2404 (and steps 2412 and 2420) may include identifying at least one of the disabled PS groups (and/or at least one of the available PS groups) based on the composite FET. Here, the composite FET includes the sum of a period in which the sampling PS of the PDD is sensitive to light and a period excluding an intermediate time between the period in which the sampling PS is not sensitive to light.

In steps 2404 , 2412 and/or 2420 , the identification of usable and unusable PS groups may be based, in part, on temperature assessment. Optionally, method 2400 may include processing one or more frames (e.g., in a dark frame or a dark PS not imaging FOV) to determine a temperature estimate (e.g., a previous frame or a current frame). by evaluating the dark current level at). Method 2400 may include using the temperature evaluation to identify usable and unusable PS groups for subsequent frames, which affects the generation of each image. The temperature evaluation can be used to evaluate how quickly the dark current will saturate the dynamic range of a given PS over the duration of the associated FET. Optionally, the temperature estimate can be used as a parameter to utilize a usability model of the PS (eg, the model generated in method 2500 ).

The timing of execution of step 2404 with respect to the timing of execution of step 2402 may vary. For example, step 2404 may optionally be performed before, concurrently with, partially concurrently with, or after step 2402 is performed. Referring to the examples of the accompanying figures, step 2404 may optionally be performed by processor 2304 and/or controller 2314 . An example of a method for effecting the identification of step 2404 is discussed with respect to method 1100 .

Step 2406 includes discarding the first frame detection level of the first group of unusable PSs and generating a first image based on the first frame detection level of the first group of usable PSs. Generation of the first image may be implemented using any suitable method, and optionally based on additional information (eg, data received from an active lighting unit, data from additional sensors such as humidity sensors, if used). can do. Referring to the example described in connection with the previous figures, it should be noted that step 2406 may optionally be implemented by processor 2304 . The generating step may include other steps of processing the signal (eg, weighting, denoising, correcting, digitizing, capping, leveling, etc.).

It should be noted that with respect to the first group of unusable PS, the replacement value can be calculated in any suitable manner (if necessary), since the data detected by this PS is discarded in the creation of the first image. This replacement value may be, for example, based on the first frame detection level of the surrounding PS, or on the previous detection level of the same PS (eg, if available in the previous frame) or of one of the one or more surrounding PSs. Based on (eg, based on a kinematic analysis of the scene), it may be calculated. For example, a Wiener filter, a local averaging algorithm, a non-local averaging algorithm, or the like may be used. Referring to image generation based on PDA data, optionally generating any one or more of these images (eg, first image, second image and third image) may include, for each image, at least one other identified as usable. calculating a replacement value for at least one pixel associated with the PS identified as unusable for each image based on the detection level of the surrounding PS. if non-binary availability assessment is used (identification in steps 2404, 2412 and/or 2420 includes identifying at least one PS as belonging to a third group of partially usable PS); The detection signal of each of these PSs identified as partially usable may be combined or averaged with the detection signal of the surrounding PS and/or other readings of the same PS that were available (or partially usable) at other times.

Optionally, the generation of the first image (or subsequent generation of the second and third images) is determined to be defective, inoperable or otherwise unusable, or determined to have a defective, inoperable or unusable detection path. It may include discarding the output of the PS. Examples of additional methods for detecting defects in PS and/or associated detection pathways are discussed with respect to method 2200 , which may be combined with method 2400 . The output of method 2200 may be used for generation in steps 2406 , 2414 and 2422 . In such a case, method 2200 may be executed periodically and may provide an output for image generation, or may be specifically triggered for use in image generation according to method 2400 .

Optionally, the generation of the first image (or subsequent generation of the second image and the third image) is determined for each image as unusable based on the level of detection of the PS measured when the PS was identified as available. calculating a replacement value for at least one pixel associated with PS. This information may be used together with the information of the neighboring PS, or may be used independently of it. Using the detection level of PS at different time points can take into account, for example, the detection level from the previous frame (e.g. in the case of a still scene), high-contrast image (HDRI) or multi-wavelength composite image (with different spectral filters). using detection information from another snap of a series of image acquisitions used to create a composite image (such as taking multiple pictures and then combining them into a single image).

It should be noted that in the first image (or any other frame generated based on the detection data of the PDA), a single pixel may be based on detection data from a single PS or PS combination. Likewise, information from a single PS can be used to determine the pixel color of one or more pixels on an image. For example, a field of view of Θ x Φ degrees can be covered by X x Y PS and converted to M x N pixels in the image. The pixel value for one of these M x N pixels may be calculated as the sum of Pixel-Value(i,j)=Σ(a□,□·DL□,□) for one or more PSs, where DL□, □ is the detection level of PS(p,s) for the corresponding frame, and a□,□ is the average coefficient for a specific pixel (i,j).

After step 2406, the first image may be provided to an external system (eg, a screen monitor, memory unit, communication system, image processing computer). The first image may be processed using one or more image processing algorithms. After step 2406, the first image may be otherwise processed as desired.

Steps 2402 - 2406 may be repeated multiple times for many frames captured by the photodetector sensor, whether consecutive frames or not. It should be noted that in some examples, for example where wide dynamic range (HDR) imaging techniques are implemented, the first image may be generated based on the detection level of several frames. In another implementation, the first image is generated by a first frame detection level of a single frame. Multiple instances of steps 2402 and 2406 may follow a single instance of step 2404 (eg, using the same FET for multiple frames).

Step 2408 is executed after receiving the first frame information and includes determining a second FET that is longer than the first FET. Determining the second FET includes determining the exposure duration (eg, milliseconds, fraction thereof, or multiples thereof) of the associated PD. Step 2408 may also include, but does not necessarily include, determining an additional timing parameter (eg, a start time for exposure). A second FET that is longer than the first FET may be selected for any reason. These reasons may include, for example, one or more of the following: total light intensity at the FOV, light intensity at a portion of the FOV, adoption of bracketing techniques, adoption of high dynamic range imaging techniques, changes in aperture, etc. The second FET may be relatively low (eg, ×1.1 times, ×1.5 times), several times or more (eg, ×2, ×5) or any higher value (eg, ×20, ×100, ×5,000), or longer than the first FET by any ratio. Referring to the example of the accompanying drawings, step 2408 may optionally be performed by controller 2314 and/or processor 2304 . Optionally, the external system may determine the first FET or influence the setting of the FET by the EO system 2300 (eg, a control system of a vehicle in which the EO system 2300 is installed).

Optionally, it should be noted that at least one of steps 2408 and 2416 may be replaced by determining a new FET (second FET and/or third FET respectively) with such an external entity. This external entity may be, for example, an external controller, an external processor, or an external system. Optionally, it should be noted that at least one of steps 2408 and 2416 may be replaced by receiving from an external entity an indication of a new FET (second FET and/or third FET respectively). . The indication of the FET can be explicit (e.g., duration in milliseconds) or implicit (e.g., indication of aperture opening and/or change in exposure value (EV), indication of change in lighting duration corresponding to the FET). have. Optionally, at least one of steps 2408 and 2416 receives, from an external entity, an indication of a change to the expected dark current (or, for example, at least a portion of the dark current delivered to the capacitance of the PS if a dark current mitigation strategy is implemented). can be replaced by

Step 2410 includes receiving second frame information. The second frame information includes, for each of the plurality of PSs of the PDA, a second frame detection level indicating an intensity of light detected by each PS during the second FET. The second frame (while detection data for the second frame information is being collected) may immediately follow the first frame, but this is not necessarily the case. Any FET in the one or more intermediate frames (if any) between the first frame and the second frame may be the same as the first FET, the second FET, or any other FET (longer or shorter). Referring to the example of the accompanying figures, step 2410 may optionally be performed by processor 2304 (eg, via read circuit 2318 ).

Step 2412 includes identifying, from among the plurality of PSs of the PDD, at least two types of PSs of the PDA based on the second FET:

a. PS group usable for the second frame containing the first PS (referred to as "usable PS second group").

b. A PS group that is unavailable for a second frame comprising the 2nd PS, the 3rd PS and the 4th PS (referred to as "Second Group of Unusable PS").

That is, the second PS and the third PS identified as belonging to the first group of available PSs in step 2404 (ie, the aforementioned usable PS group for the first frame) are the longer PSs for the second frame. Because of the FET, it is identified in step 2412 as belonging to the unusable PS (ie, the unusable PS group for the aforementioned second frame). The identification of step 2412 may be implemented in other manners, such as any one or more of those discussed above with respect to step 2404 . A PS that was considered usable for a shorter FET may be considered unavailable at step 2412 for a longer FET for a variety of reasons. For example, if such a PS has a charge storage capacity (eg, capacitance) that is lower than the average charge storage capacity of the PS in a PDA, the charge storage capacity of this PS will be both the dark current and the detection signal accumulated over a longer integration time. may be considered insufficient. Since it cannot maintain sufficient dynamic range, a PS that becomes unavailable in the first FET is identified as unavailable even to a longer second FET if the dark current level is maintained (e.g., the temperature and bias of the PD are not changed). do.

Step 2412 is executed after step 2408 (because it is based on the output of step 2408). The timing of execution of step 2412 with respect to the timing of execution of step 2410 may vary. For example, step 2412 may optionally be performed before, concurrently with, partially concurrently with, or after step 2410 is performed. Referring to the example of the accompanying drawings, step 2412 may optionally be performed by processor 2304 . An example of a method for performing the identification of step 2412 is discussed with respect to method 2500 .

Step 2414 includes discarding the second frame detection level of the second group of unusable PSs and generating a second image based on the second frame detection level of the second group of usable PSs. Importantly, step 2414 includes generating the second image, discarding the outputs (detection levels) of the at least two PSs having the outputs used in the creation of the first image. These at least two PSs are identified as usable based on the FETs of the first frame and are identified as usable for generation of the first image (ie, at least the second PS and the third PS). Generation of the second image may be implemented using any suitable method, including any of the methods, techniques, and variations discussed above with respect to generation of the first image. With respect to the second group of unusable PS, a replacement value can be calculated in any suitable manner (if necessary), since the data detected by that PS is discarded when generating the second image. After step 2414, the second image may be provided to an external system (eg, a screen monitor, memory unit, communication system, image processing computer) and processed using one or more image processing algorithms, or processed as desired. can be

Steps 2410 - 2414 may be repeated multiple times for many frames captured by the photodetector sensor, whether consecutive frames or not. It should be noted that in some examples, for example, where wide dynamic range (HDR) imaging techniques are implemented, the second image may be generated based on the detection level of several frames. In another implementation, the second image is generated by a second frame detection level of a single frame. Multiple instances of steps 2410 and 2414 may follow a single instance of step 2412 (eg, using the same second FET for multiple frames).

Step 2416 is executed after receiving the second frame information and includes determining a third FET that is longer than the first FET and shorter than the second FET. Determining the third FET includes determining the exposure duration (eg, milliseconds, fraction thereof, or multiples thereof) of the associated PD. Step 2416 may also include, but does not necessarily include, determining additional timing parameters (eg, start time for exposure). The third FET may be selected for any reason as discussed above with respect to the determination of the second FET in step 2408 . The third FET may be relatively low (eg, ×1.1 times, ×1.5 times), several times or more (eg, ×2, ×5) or any higher value (eg, ×20, ×100, ×5,000). ) or may be longer than the first FET by any ratio. The third FET may be relatively low (eg, ×1.1 times, ×1.5 times), several times or more (eg, ×2, ×5) or any higher value (eg, ×20, ×100, ×5,000). ) or may be shorter than the second FET by any ratio. Referring to the examples of the accompanying figures, step 2416 may optionally be performed by controller 2314 and/or processor 2304 . Optionally, the external system may determine the first FET or influence the setting of the FET by the EO system 2300 .

Step 2420 of method 2400 includes receiving third frame information. The third frame information includes, for each of the plurality of PSs of the PDA, a third frame detection level indicating the intensity of light detected by each PS during the third FET. The third frame (while detection data for the third frame information is being collected) may immediately follow the second frame, but this is not necessarily the case. Any FET in the one or more intermediate frames (if present) between the second frame and the third frame may be the same as the second FET, the third FET, or any other FET (long or short). Referring to the example of the accompanying figures, step 2420 may optionally be performed by processor 2304 (eg, via read circuit 2318 ).

Step 2420 includes identifying, based on the third FET, at least two types of PSs of the PDA from among the plurality of PSs of the PDD:

a. A PS group usable for a third frame comprising the first PS and the second PS (referred to as "third group of available PSs").

b. Unusable PS group (referred to as "third group of unusable PS") for the third frame including the third PS and the fourth PS.

That is, the second PS identified as belonging to the first group of PSs available for use in step 2404 (ie, the group of PSs available for the first frame described above) in the step 2404 is further related to the third frame with respect to the first frame. Due to the long FET, it is identified in step 2420 as belonging to the third group of unusable PS (ie, the unusable PS group for the aforementioned third frame). The third PS identified in step 2412 as belonging to the second group of unusable PSs (ie, the group of unusable PSs for the aforementioned second frame) is added to the third frame with respect to the second frame. Due to the short FET, it is identified in step 2420 as belonging to the third group of available PSs (ie, the usable PS group for the aforementioned third frame).

The identification of step 2420 may be implemented in other manners, such as any one or more of those discussed above with respect to step 2404 . A PS that was considered usable for a shorter FET may be considered unavailable in step 2420 for a longer FET for a variety of reasons, eg, as discussed above with respect to step 2412 . PS that was considered unavailable for longer FETs may be considered usable at step 2420 for shorter FETs for a variety of reasons. For example, if such a PS has a greater charge storage capacity (eg, capacitance) than some PSs in the second group of unusable PSs, the charge storage capacity of the different PSs may have a dark current accumulated for a shorter integration time than the second FET. and the detection signal.

Step 2420 is executed after step 2416 (as it is based on the output of step 2416). The timing of execution of step 2420 may vary with respect to the timing of execution of step 2416 . For example, step 2420 may optionally be performed before, concurrently with, partially concurrently, or after step 2416 is performed. Referring to the example of the accompanying drawings, step 2420 may optionally be performed by processor 2304 and/or controller 2314 . An example of a method for performing the identification of step 2420 is discussed with respect to method 1100 .

Step 2422 includes discarding the third frame detection level of the third group of unusable PSs and generating a third image based on the third frame detection level of the third group of usable PSs. Importantly, step 2422 discards the output (detection level) of the at least one PS with the output used to generate the first image (eg, the second PS), and discards the output (detection level) of the second image (eg, the third PS). generating the third image while utilizing the output of the at least one PS having the discarded output when generating the PS). Generation of the third image may be implemented using any suitable method, including any of the methods, techniques, and variations discussed above with respect to generation of the first image. With respect to the third group of unusable PS, it should be noted that the replacement value can be calculated in any suitable manner (if necessary), since the data detected by this PS is discarded in the third image generation. After step 2422, the third image may be provided to an external system (eg, a screen monitor, memory unit, communication system, image processing computer). After step 2422, the third image may be processed using one or more image processing algorithms. After step 2422, the third image may be otherwise processed as desired.

Optionally, the generation of the one or more images (eg, the first image, the second image, the third image) in the method 2400 is based on a previous step of evaluating dark current accumulation in at least one of the PSs for each image. (eg, based on at least each FET, electrical measurements during or close to capturing the optical signal, etc.). For example, such measurements may include measuring dark currents (or other indication measurements) at a reference PS held within the dark. Generation of each image may include subtracting a magnitude associated with the dark current evaluation for the PS from the detection signal of one or more PSs to more accurately represent the FOV of the PDA. Optionally, this step of correcting for dark current build-up is performed only for the PS available for each image.

In a PDA characterized by a relatively high dark current (e.g., as a result of the type and nature of the PD), the capacitance of the individual PSs from which the detection charge is collected can be (partially or fully) saturated by the dark current (system It leaves little or no dynamic range for detecting ambient light). Even when means are implemented to subtract the dark current level from the detection signal (eg, to normalize the detection data), the lack of dynamic range for detection indicates that the resulting signal is either fully saturated or insufficient for meaningful detection of the ambient light level. means to Because the PD's dark current accumulates in the capacitance (parasitic or residual capacitance of the actual capacitor or other components of the PS) during the FET, this method uses the FET to determine if the PS is available for each FET. After the charge of the dark current (or at least the relevant part) is collected during the entire FET, there is sufficient dynamic range left in the capacitance. Identifying groups of PSs that are unavailable for a frame involves identifying PSs whose dynamic range is below an acceptable threshold (or otherwise expected to fail to meet the dynamic range satisfaction reference), given the FETs of each frame. may include Similarly, identifying the groups of PSs available for a frame identifies PSs whose dynamic range exceeds an acceptable threshold (or is otherwise expected to meet the dynamic range satisfaction reference) given the FETs of each frame. may include doing The two permissible thresholds mentioned above may be the same threshold or different thresholds (e.g. if PSs with dynamic range between those thresholds are treated differently, e.g. partial for related frames) identified as belonging to the available PS group).

Referring throughout method 2400, it should be noted that additional instances of steps 2416, 2418, 2420, and 2422 may be repeated during additional FETs (eg, fourth FETs, etc.). This time may be longer, shorter, or equal to any of the previously used FETs. It should also be noted that, optionally, the first FET, the second FET and the third FET are continuous FETs (ie, no other FET is used by the PDA between the first FET and the third FET). Alternatively, another FET may be used between the first FET and the third FET.

It should be noted that different groups of usable PS and unusable PS may be determined for different FETs, although the exposure value EV remains the same. For example, suppose that the first FET is extended by a factor q to provide a second FET, but the number of f is increased by a factor q, such that the total illumination that the PDA receives is substantially the same. In this case, even if EV remains constant, the second group of unusable PS will contain PSs other than those contained in the first group of unusable PS because dark current accumulation increases by a factor q.

A non-transitory computer readable medium is provided for generating image information based on data of the PDA, which, when executed on a processor, for each of a plurality of PSs of the PDA, the amount of light detected by each PS during a first FET. receiving first frame information including a first frame detection level indicative of strength; Based on the first FET, from among the plurality of PSs of the PDD, a first group of usable PSs including the first PS, the second PS and the third PS and a first group of the unavailable PSs including the fourth PS are selected. identifying; discarding the first frame detection level of the first group of unusable PSs and generating a first image based on the first frame detection level of the first group of usable PSs; after receiving the first frame information, determining a second FET that is longer than the first FET; receiving, for each of the plurality of PSs of the PDA, second frame information comprising a second frame detection level indicative of an intensity of light detected by each PS during a second FET; Based on the second FET, among the plurality of PSs of the PDD, a second group of usable PSs including the first PS, and a second of unavailable PSs including the second PS, the third PS and the fourth PS identifying a group; discarding a second frame detection level of the second group of unusable PSs, and generating a second image based on the second frame detection level of the second group of available PSs; after receiving the second frame information, determining a third FET that is longer than the first FET and shorter than the second FET; receiving, for each of the plurality of PSs of the PDA, third frame information comprising a third frame detection level indicative of an intensity of light detected by each PS during a third FET; Based on the third FET, among the plurality of PSs of the PDD, a third group of usable PSs including the first PS and the second PS, and a third group of unavailable PSs including the third PS and the fourth PS identifying a; and discarding a third frame detection level of the third group of unusable PSs, and generating a third image based on the third frame detection level of the third group of available PSs. do.

The non-transitory computer-readable medium of the preceding paragraph may include additional instructions that, when executed on a processor, perform any other steps or variations discussed above with respect to method 2400 .

25 is a flow diagram illustrating a method 2500 for generating a model for PDA operation in different FETs, in accordance with examples of the invention disclosed herein. Identifying PSs belonging to a group of usable PSs given a given FET (and additional parameters such as temperature, bias, PS capacitance, etc. of the PD) may be based on the operating model of each PS in a different FET. Such modeling may be part of method 2400 or may be performed separately prior to that. Steps 2502 , 2504 , and 2506 of method 2500 are performed for each of a plurality of PSs of a PDA (eg, PDA 1602 ), and possibly for all PSs of the photo detector array.

Step 2502 includes determining the availability of each PS for each FET of a plurality of different FETs. The availability determination may be performed in other ways. For example, the detection signal of a PS can be an expected value (e.g., if the lighting level is known - perhaps completely dark or a known higher lighting level), the average of the other PSs, the detection level of the other PSs (eg all PSs). is imaging a color-uniform target), determine whether the detection result of the other FET (eg, the detection level (eg, 200 nanoseconds) at period T is about twice the detection level (eg, 330 nanoseconds) at T/2) ) can be compared. The determined availability may be a binary value (eg, enabled or disabled), a non-binary value (eg, a scalar that evaluates and indicates an availability level), a set of values (eg, a vector), or any other It may be in any suitable form. Optionally, the same plurality of frame FETs are used for all of the plurality of PSs, but this is not necessarily the case. For example, in a non-binary usability assessment, an intermediate value between fully unavailable and fully usable is that the detection signal of each PS is available (partially available) at a different time than the detection signal of the surrounding PS. It may indicate that it should be combined or averaged with other readings of the same PS that did.

Method 2500 may include an optional step 2504 of measuring charge accumulation capacity and/or saturation parameters for each PS. The charge capacity is measured in any suitable manner using current from the PD, another source of the PS (eg, a current source), another source of the PDA, or an external source (eg, a calibration machine at the manufacturing facility where the photodetector is manufactured). can be For example, if the capacitance difference between the different PSs is negligible or simply discarded, step 2504 may be omitted.

Step 2506 includes generating an availability prediction model for each PS, which, when operated under different FETs, uses a PS not included in the plurality of FETs whose availability is actively determined in step 2502 . It provides an estimate of the likelihood. Different FETs may be included in the same range as the duration of the plurality of FETs in step 2502, longer or shorter therefrom. The generated availability prediction model may be, for example, a binary value (e.g., enabled or disabled), a non-binary value (e.g., a scalar that evaluates or indicates the level of availability), a set of values (e.g., Different types of indications of availability may be provided, such as in a vector) or other suitable format. The availability type indicated by the model may be the same as or different from the availability type determined in step 2502 . For example, step 2502 may include evaluating the dark current collected at different FETs, whereas step 2504 may involve determining a time threshold representing the maximum allowable FET at which this PS is considered usable. may include Optionally, the usability model may consider the charge storage capacity of each PS.

Any suitable approach may be used to generate the availability predictive model. For example, different dark currents can be measured or evaluated for a PD during different FETs, and then a regression analysis can be used to determine a function (polynomial, exponential, etc.) that can estimate the dark current in other FETs.

Optional step 2508 includes compiling a availability model for at least a portion of the PDA, including at least a plurality of PSs from the previous step. For example, step 2508 may include generating one or more matrices or other types of maps that store model parameters in cells for each PS. For example, if step 2506 is a dark current linear regression function for each PS(p,s) [DarkCurrent(p,s)=A□,□·τ+B□,□, where τ is a FET and A□ , , and B , where are the linear coefficients of the linear regression), matrix A can be created to store different values of A , , and matrix B with different values of B , . can be created to store If necessary, a third matrix C may be used to store different capacitance values C , □ (or different saturation values S , ) for different PSs.

After step 2506 (or step 2508 if implemented), based on the results of step 2506 (or step 2508 if implemented), one of the plurality of FETs of step 2502 is An optional step 2510 may follow which includes determining the availability of multiple PSs for FETs that are not. For example, step 2510 may include creating a mask (eg, a matrix) of unusable PSs for different PSs of the photo detector array.

Referring throughout method 2500, step 2502 may include determining the dark current for each PS of the PDA in four different FETs (eg, 33ns, 330ns, 600ns, and 2000ns). Step 2504 may include determining a saturation value for each PS, and step 2506 may include generating a polynomial regression for dark current accumulation over time for each PS. In this example, step 2508 may include creating a matrix and (according to regression analysis) storing in each cell a FET whose dark current will saturate the PS. Step 2510 may include receiving a new FET, determining for each cell of the matrix whether it is lower or higher than a stored value, then for each unavailable PS (FET is higher than the stored value) Create a binary matrix that stores a first value (eg, “0”) and a second value (eg, “1”) for each available PS (the FET is lower than the stored value).

Any step of method 2500 may occur during manufacture of the PDA (eg, during factory calibration), during operation of the system (eg, after the EO system including the PDA is installed in a designated location such as a vehicle, monitoring system, etc.) ), or at any other suitable time between or after that time. Different steps may be performed at different times.

Referring throughout method 2400, it should be noted that the different steps may be extended mutatis mutandis to measuring the effect of dark current on different PSs in different FETs under different operating conditions (e.g., at different temperatures). when different biases are applied to the PD), mutatis mutandis.

Optionally, as part of the method 2400 determining the FETs (eg, second FET, third FET) may include maintaining the number of unavailable PSs for each frame below a predetermined threshold, while maintaining maximizing the FET. For example, to maximize collection of signals, method 2400 allows for a predetermined number of unusable PSs (eg, at least 99% of PDA PSs available and up to 1% of PSs unavailable). setting the FET to approach a threshold associated with In some cases, maximization does not yield an exact maximum duration, but may yield durations close to it (eg, 320% or more or 325% or more of the mathematical maximum duration). For example, a maximum frame duration among discrete predefined time ranges may be selected.

For example, determining a FET as part of method 2400 may include determining a FET that is longer than other possible FETs, thereby inducing more PS than the previous FET, thereby causing more PS compared to other possible FETs. Allows a large number of PSs to be considered unusable, but improves the image quality of the remaining PSs. This can be useful, for example, in relatively dark conditions. Optionally, it should be noted that the determination of a FET (eg, by an attempt to maximize it) may take into account the spatial distribution of PS that is considered unusable in other FETs. For example, knowing that in some areas of a PDA, there is an accumulation in PS with a high percentage of PS that is considered unusable above a certain FET, especially if this is a significant part of the FOV (e.g., the center of the FOV, or the previous frame). (where a pedestrian or a vehicle is identified), it is possible to determine a FET that is lower than the corresponding threshold.

Method 2400 may include generating a single image based on detection levels in two or more frames detected in different FETs, wherein different groups of unavailable PSs are used during different FETs. For example, three FETs can be used as x1, x10, and x100. The color determined for each pixel of the image is the detection level of one or more PSs (e.g., the PS detects a non-negligible signal in an usable and unsaturated FET) or the detection level of an adjacent PS (e.g., each PS Even when it is determined that α is available, it does not provide a usable detection signal, since the signal may be ignored at such a time). Method 2400 can include determining a plurality of FETs for combining different exposures for a single image (eg, using a wide dynamic range imaging technique-HDR). The determination of such FETs may be based on modeling the availability of other PSs in other FETs, such as the model generated in method 2500 . Method 2400 may also include determining to capture a single image at two or more distinct detection instances each providing sufficient PS available. For example, instead of taking a single capture of the scene using a 2 millisecond FET, the method 2400 includes determining to capture the scene twice (eg, two 1 ms FETs, 1.5 ms and 0.5 ms FETs). , whereby the number of PSs available at each exposure will exceed a predetermined threshold.

Optionally, the method 2400 includes one of the FETs based on availability models of different PSs in different FETs (eg, generated in method 2500) and saturation data of at least one previous frame captured by the PDA. determining at least one. The saturation data includes information about the PS saturated in at least one FET of at least one previous frame (eg, number of PSs, any PS, any part of PDA) and/or substantially in at least one FET of at least one previous frame. Contains information about saturated PS. Since the saturation data can be related to the immediately preceding frame (or several frames), it represents the saturation behavior for the curtain image scene.

Method 2400 may further include modeling (eg, by implementing method 2500 or any other suitable modeling method) the availability of the PDA's PS in different FETs. Providing a availability model of the PS of the PDA in another FET (whether as part of method 2400 or not), method 2400 includes (a) the FET of at least one of the second FET and the third FET based on the results of the modeling. determining a; and/or (b) identifying at least one of the unavailable PS groups based on the modeling result.

Optionally, in determining any one or more FETs, method 2400 determines that extending FETs and longer FETs (e.g., based on the model of method 2500) are not available due to the darkness of the FOV scene. between reducing the FET to limit the amount of PS, determining a FET that balances. For example, when operating at the same temperature and bias in the PD (so that the dark current of each FET remains constant), step 2408 may take longer because the scene has become darker (due to the larger number of unusable PS). Determining a FET may include determining a FET, and step 2416 may include determining a shorter FET, since the scene is brightened again (thus the number of unavailable PSs is reduced). This is particularly relevant in darker images, when the availability of PS, which arises from dark current build-up (from temperature and operating conditions, but not from lighting level), limits the elongation of the FET. Here, the extension of the FET is performed when dark current accumulation does not significantly limit the dynamic range of each PS. In another example, within the time span during which the scene lighting is held constant, step 2408 causes the longer FETs enabled by the temperature drop (thus lowering the dark current and lowering the percentage of unusable PS in each FET). may include determining, and step 2416 may include determining a shorter FET as the temperature of the PDA rises again.

26 is a graphical representation of an implementation of a method 2400 for three frames of the same scene in different FETs, in accordance with an example of the invention disclosed herein. The example scene contains four concentric rectangles, each darker from the one surrounding it. The other diagrams in FIG. 26 correspond to steps in method 2400 and have been numbered with equivalent reference numbers using apostrophes. For example, diagram 2406' corresponds to execution of step 2406 and the like. Each rectangle in the lower nine diagrams represents a single PS, or a pixel that maps directly to that PS (in the lower three diagrams). In all diagrams, the position of the PS relative to the PDD remains constant.

Common to many types of PDA's, the PDA from which frame information is received may contain a bad, defective or other malfunctioning PS (also called a bad, combined, or other malfunctioning pixel). The term "malfunctioning PS" generally relates to PSs that deviate from the expected response, including, but not limited to, fixed, dead, hot, on, warm, faulty, and flashing PSs. A malfunctioning PS may be an individual PS or a PS cluster. Non-limiting examples of defects that can cause a PS to malfunction include PS bump bond connections, error addressing in multiplexers, vignetting, severe sensitivity defects in some PSs, nonlinearities, poor signal linearity, low full well, poor mean-strain linearity. , excessive noise and high dark current. The one or more PSs identified as unusable in method 2400 may be PSs that are permanently malfunctioning or PSs that malfunction based on conditions unrelated to the FET (eg, due to high temperature). Such a PS may be identified as unavailable for all FETs in method 2400 (eg, PS 8012.5). Nevertheless, some functional PSs (which do not "misbehave") may be considered unavailable for all FETs in method 2400 due to their limited capacity and sufficiently long FETs (eg, PS 8012.4). Optionally, the method 2400 may include determining the availability of one or more of the PSs of the PDA based on other parameters in addition to the FETs (eg, temperature, electrical parameters, ambient light levels). It should be noted that, in this case, PS considered unusable for reasons of FET cannot be considered usable because of other considerations (eg temperature), usually due to capacitance limitations.

In the illustrated example:

a. PS 8012.5 does not output a signal regardless of the amount of light colliding from all three FETs (T₁, T₂, T₃); possible under all conditions.

b. The PS 8012.4 outputs a saturated signal regardless of the amount of colliding light from all three FETs (T₁, T₂, T₃); possible under all conditions.

c. The PS 8012.3 outputs a usable signal from the shortest FET, T₁, but outputs an unavailable (saturated) signal on the longer FETs, T₂ and T₃.

d. The PS 8012.2 outputs usable signals on the shorter FETs, T₁ and T₃, but outputs an unavailable (saturating) signal on the longest FET, T₂.

It should be noted that other types of faults and erroneous outputs may also occur. These errors may include, for example, very non-linear signal response outputs, consistently too strong signal outputs, consistently too weak signal outputs, random or semi-random outputs, and the like. Also, many PSs (eg, first PS 8012.1) may be available in all FETs used for detection.

23 , it is noted that optionally system 2300 may be an EO system with dynamic PS availability assessment capability. That is, the EO system 2300 may alternately assign different PSs to be enabled or disabled, based on the FET and possibly other operating parameters, each PS being used at capture (eg, according to the availability model). The detection signal of the PS can be utilized only when it is determined that it is possible.

In this case, the EO system 2300 includes:

a. A PDA (2302) comprising a plurality of PSs (2306) each operative to output a detection signal in a different frame. The detection signal output for each frame by each PS 2306 indicates, during each frame, the amount of light impinging on each PS (and possibly the dark current of the PD of each PS).

c. Availability filtering module (eg, implemented as part of processor 2304 or separately). The availability filtering module determines, for each PS 2306, that the PS is unavailable based on a first FET (which may be different between different PSs 2306), and later on a second FET shorter than the first FET. act to determine that the same PS 2306 is available based on it. That is, a PS 2306 that was unavailable at one point (its output was discarded when generating one or more images) may later be available again (eg, as the FET becomes shorter), and such PS 2306 The output of may be useful again in the creation of the next image.

c. A processor (2304) operative to generate an image based on the frame detection level of the plurality of PSs (2306). Among other configurations of the processor 2304 , it may (a) generate a first image based on a first frame detection level, when generating a first image of a filtered PS determined as unusable for the first image by the availability filtering module. for the second image by the availability filtering module, excluding the detection signal, and (b) generating the second image based on the second frame detection level captured by the PDA after the capture of the first frame detection level. and a second detection signal of the filtered PS determined to be usable.

Optionally, the controller 2314 may determine different FETs for different frames based on different illumination levels of objects in the field of view of the EO system.

Optionally, the controller 2314 controls the EO by maximizing the FETs while maintaining the number of unusable PSs below a predetermined threshold for each frame (eg, as discussed with respect to the method 2400 ). can be configured to determine the FET for the system.

Optionally, EO system 2300 is configured to provide signal levels of at least one shielded PD, as well as at least one shielded PD that is shielded from ambient lighting (eg, by a physical barrier or using deflection optics). based on a dedicated circuit operative to output an electrical parameter indicative of the level of dark current. The processor 2304 may be configured to generate an image based on the electrical parameter, the detection signal of each of the FETs and the PDA, thereby compensating for different degrees of dark current accumulation in different frames.

Optionally, the processor 2304 is operative to calculate a replacement value for at least one pixel of the first image associated with the filtered PS based on the detected level of the filtered PS measured when the PS is identified as usable. can Optionally, the processor 2304 may be configured to calculate a replacement value for the PS, based on the detection level of the surrounding PS, when the detection signal by each PS is excluded from image generation. Optionally, the processor 2304 is operable to calculate a replacement value for at least one pixel of the first image associated with the filtered PS based on the first frame detection level of the adjacent PS.

Optionally, the processor 2304 (or, if not part of the processor, a availability filter module) may be operable to determine a degree of availability for the PS based on the FET, wherein the degree of availability is determined by the sampling PS of the PDD. Include the sum of the period during which the sampling PS is light-sensitive and the period excluding the intermediate time between the period in which the sampling PS is not light-sensitive.

Optionally, the processor 2304 may utilize the availability model generated according to method 2500 to determine when to include and when to exclude detection signals of different PSs captured at different FETs. Optionally, the EO system 2300 is operable to perform the method 2500 . Optionally, the EO system 2300 may be configured to participate in the execution of the method 2500 in conjunction with an external system (eg, a factory calibration machine used in the manufacture of the EO system 2300 ).

27 is a flow diagram illustrating an example of a method 3500 in accordance with the invention disclosed herein. Method 3500 is used to generate images based on different subsets of PS at different operating conditions. Referring to the example described in connection with the previous figures, method 3500 may be executed by processor 1604 , where the PDA of method 3500 may optionally be PDA 1602 . Method 3500 includes at least steps 3510 , 3520 , 3530 and 3540 , which are repeated in sequence for different frames captured by the photo detector array. The sequence can be run globally for every frame in the stream, but this is not necessarily the case, as detailed below.

The sequence begins with receiving ( 3510 ) from the PDA frame information representing a detection signal for a frame, provided by a plurality of PSs of the PDA. The frame information may include a detection level (or levels) for each PS (eg, between 0 and 1024, three RGB values, between 0 and 255 each, etc.) or any other format. The frame information may represent the detection signal in an indirect manner (eg, information about the detection level of a given PS may be given for the level of a surrounding PS or for the level of a previous PS). The frame information may also include additional information (eg, serial number, timestamp, operating conditions), some of which may be used in subsequent steps of method 3500 . The PDA from which the frame information is received may contain a defective, defective or other malfunctioning PS.

Step 3520 includes receiving actuation condition data indicative of an actuation condition of the PDA during the frame duration. The operating conditions may be received from other types of entities, such as any one or more of the following entities: a PDA, a controller of the PDA, at least one processor executing the method 3500 , one or more sensors, executing the method 3500 . At least one processor, one or more controllers, etc. Non-limiting examples of operating conditions that may be mentioned in step 3520 include, but are not limited to, the PDA's FET (eg, electronic or mechanical shutter, flash illumination duration, etc.), the amplification gain of the PDA or connected circuitry, the applied gain to the PDA's PD. These include biases, ambient light levels, dedicated illumination levels, image processing modes of the downstream image processor, filtering applied to the light (eg, spectral filtering, polarization), and the like.

Step 3530 includes determining, based on the operating condition data, a defective PS group including at least one PS and excluding a plurality of other PSs. When step 3530 is executed for different frames, based on different operating condition data received for these frames in different corresponding instances of step 3520, different groups of defective PSs for different frames with different operating conditions from each other is chosen However, the same group of defective pixels may be selected for two frames with different operating conditions (eg, when the difference in operating conditions is relatively small).

Since the above determination is made based on operating condition data and not based on evaluation of the PS itself, the defects of various PSs included in other groups are not references to actual operating conditions, but estimates of those conditions. Therefore, the PS included in the defective PS group in step 3530 is not necessarily defective or not working under the operating condition indicated in the operating condition data. The decision of step 3530 is intended to match the actual current state of the PDA as precisely as possible.

Step 3540 includes processing the frame information to provide an image representing the frame. The above processing is based on the detection signal of the PS of the photodetector except for the PS included in the defective PS group. That is, the detection signal from the PS of the PDA is used to create an image representing the field of view (or one or more objects or other scenes whose light reaches the PDA), but all detections originating from the PS included in the group of defective PSs. Signal avoidance (as mentioned earlier, this is dynamically determined based on operating condition data during the time the relevant frame information was captured). Step 3540 may optionally include calculating a replacement value to compensate for the discarded detection signal. Such computing may include determining a replacement value for the defective PS, for example, based on detection signals of the surrounding PS. Such calculation may include determining replacement values for pixels of the image, for example, based on values of surrounding pixels of the image. Any of the techniques discussed above with respect to generating an image in method 2400 may also be used to generate an image in step 3540 .

Examples for execution of the method on two frames (a first frame and a second frame) may include, for example:

a. Receive from the PDA first frame information provided by the plurality of PSs and indicating a first detection signal belonging to a first frame duration, wherein the plurality of PSs include at least a first PS, a second PS and a third PS . Frame duration is the amount of time the light collected by the PDA is aggregated into a single image or video frame. The different frame durations may be mutually exclusive, but may optionally partially overlap in some embodiments.

b. Receive first actuation condition data representing an actuation condition of the PDA during a first frame duration.

c. determine - based on at least the first operating condition data - a first group of defective PSs including the third PS and excluding the first PS and the second PS. The determination may include directly determining the first group of defective PS, or determining other data suggestive of which pixels are considered defective (e.g., a complement set of non-defective pixels). determine, assign a defect level for each pixel, and later set a threshold or other reference).

d. Process first frame information to provide a first image based on the first defective PS group. The processing is based on at least the first detection signal of the first PS and the second PS (optionally preceding pre-processing such as: digitization, capping, level adjustment, etc.), and information related to the detection signal of the third PS discard

e. Receive second frame information representing a second detection signal provided by the plurality of detection PSs from the PDA. The second frame information relates to the second frame duration rather than the first frame duration.

f. Receive second operating condition data representing an operating condition of the PDA during a second frame duration, which is different from the first operating condition data. The second actuation condition data may, but need not, be received from the same source from which the first actuation condition data was received.

g. A second group of defective PSs including the second PS and the third PS and excluding the first PS is determined based on the second operating condition data. The determination may include directly determining the second group of defective PS, or determining other data suggestive of which pixels are considered defective (e.g., a complement set of non-defective pixels). determine, assign a defect level for each pixel, and later set a threshold or other reference).

h. Process the second frame information based on the second group of defective PSs to provide a second image. The processing of the second image information is based on at least the second detection signal of the first PS, and discards information related to the detection signal of the second PS and the third PS.

28A illustrates a system 3600 and exemplary target objects 3902 and 3904 in accordance with examples of the invention disclosed herein. The EO system 3600 is operable to process detection signals from at least one PDA (which may but not necessarily be part of the same system) to produce an image representing an object in the field of view of the system 3600 . It includes at least a processor 3620 . System 3600 may be implemented by system 2300, and although like reference numerals are used (e.g., in this case, PDA 3610 may be PDA 2302, controller 3640 may be 2314)), but not necessarily. In the interest of brevity, not all descriptions provided above with respect to system 2300 are repeated, and any combination of one or more components of system 2300 may be implemented in system 3600 as desired and vice versa. It should be noted that cases are possible. System 3600 may be a processing system (eg, computer, graphics processing unit), or an EO system that further includes a PDA 3610 and optics. In the latter case, system 3600 may be any type of EO system that uses a PDA for detection, such as a camera, spectrometer, LIDAR, or the like. Optionally, system 2600 includes one or more illumination sources 3650 (eg, lasers, LEDs) for illuminating an object in the FOV (eg, to illuminate the object during at least the first FET and the second FET). ) may be included. Optionally, system 3600 can include a controller 3640 operative to determine different FETs for different frames based on different illumination levels of objects in the field of view of the EO system. Optionally, these different FETs may include a first FET and/or a second FET.

Two exemplary targets are shown in FIG. 28A: a dark colored car 3902 with a highly reflective license plate (with a low reflective body panel) and a black rectangular panel 3904 with white patches. It should be noted that system 3600 is not necessarily limited to generating images of low reflective objects having high reflective patches. However, the way the system 3600 generates an image of such a target is interesting.

The processor 3620 may output multiple detection results of an object comprising a high reflective surface surrounded by low reflective surfaces on all sides (illustrated by targets 3902 and 3904 ) to a PDA (eg, PDA 3610 , if implemented). ) is configured to receive The multiple detection result includes (a) first frame information of the object detected by the PDA during the first FET and (b) second frame information of the object detected by the PDA during a second FET longer than the first FET. The first frame information and the second frame information indicate detection signals output by different PSs of the PDA, which in turn indicate the light intensity of different portions of the target detected by the PDA. Some PSs detect light from low reflective portions of the object, while at least one other PS detects light from high reflective surfaces.

Based on the different FETs, the processor 3620 processes the first frame information and the second frame information differently. 28B shows exemplary first and second images of targets 3902 and 3904 in accordance with examples of the invention disclosed herein. When processing the first frame information, the processor 3620 processes the first frame information based on the first FET. Create a first image comprising a bright area representing a high reflectivity surface surrounded by a dark background representing a low reflectivity surface. This is shown in FIG. 28B as first images 3912 and 3914 (corresponding to objects 3902 and 3904 in FIG. 28A ). When the processor 3620 processes the second frame information based on the second FET longer than the first FET, it generates a second image including a dark background without a bright region. This is shown in FIG. 28B as second images 3922 and 3924 (corresponding to objects 3902 and 3904 in FIG. 28A ).

That is, as more light from the highly reflective surface reaches each PS of the photodetector in the second frame, the image output becomes darker, not brighter or saturated. The processor 3620 can use information from the surrounding PS (which has a signal of low intensity because it captures the low reflective surface of the object) to determine a darker color for the pixel representing the high reflective surface in the second image. , this is because we decided that the signal from the associated PS was not available in the longer second FET. Optionally, when the processor 3620 generates the second image based on the second FET (and optionally also based on availability modeling of each PS, as discussed with respect to method 2500 ): Discard the detected light signal corresponding to the high reflective surface, and calculate a dark color for at least one corresponding pixel of the second image in response to the detected light intensity from the surrounding low reflective surface of the object captured by the surrounding PS. can be configured to Optionally, the decision by processor 3620 to discard the information of each PS is not based on the detected signal level, but rather based on the sensitivity of the individual PS to dark current (eg, limited capacitance). Optionally, when processing the second frame information, the processor 3620 is configured to: detect at least one light from the high reflective surface based on the second FET, eg, similar to the identifying step of the method 2400 . It can be identified that the PS of is unavailable for the second frame.

The high reflective surface may be smaller than the low reflective surface and may be surrounded on all sides by the low reflective surface, although this is not necessarily the case. A highly reflective surface may correspond to a single PS, less than one PS in size (eg, angular magnitude), but may correspond to multiple PSs in size. The difference between the high and low reflectivity levels can vary. For example, a low reflective surface may have a reflectivity of 0 to 15%, while a high reflective surface may have a reflectivity of 80 to 100%. In another example, a low reflective surface may have a reflectivity between 50 and 55%, while a high reflectivity surface may have a reflectivity between 65 and 70%. For example, the minimum reflectivity of a high reflective surface may be x2, x3, x5, x10, or x100 of the maximum reflectivity of a low reflective surface. Optionally, the high reflective surface has at least 95% reflectance (eg, a white surface) in the spectral range detectable by the PS, and the low reflective surface has less than 5% reflectance (eg, a black surface) in the spectral range detectable by the PS. surface). It should be noted that, as discussed above, a FET may correspond to a fragmented time span (eg, corresponding to multiple illumination pulses) or a single continuous time span.

Optionally, it should be noted that the amount of optical signal level arriving from the high reflective surface to the associated PS of the first FET and the second FET may be similar. This can be accomplished by filtering the incident light by correspondingly changing the f-number of the detection optics 3670 (eg, increasing the f-number by a factor q while increasing the FET by a factor q). Optionally, the first exposure value (EV) of the PDA during capturing the first frame information differs from the second EV of the PDA during capturing the second frame information by less than 1%. Optionally, the difference in the FET is the only major difference between the operating conditions between the first frame and the second frame.

Evaluating the temperature of the PDA to calibrate the usability model for various levels of dark current was discussed above. Optionally, the processor 3620 is configured to: (a) determine a first temperature evaluation of the light detection array during capturing the first frame information and a second temperature evaluation of the light detection array during capturing the first frame information , process the detection signal reflected from the object, and (b) determine to discard the detection result corresponding to the highly reflective surface based on the second FET and the second temperature evaluation.

29 is a flow diagram illustrating a method 3700 for generating image information based on data of a PDA, in accordance with examples of the invention disclosed herein. Referring to the example described in connection with the previous figures, it should be noted that method 3700 may optionally be executed by system 3600 . Any of the variations discussed above with respect to system 3600 may be applied mutatis mutandis to method 3700 . In particular, method 3700 (and at least steps 3710 , 3720 , 3730 and 3740 ) may be executed by processor 3620 .

Step 3710 includes receiving, from the PDA, first frame information of the black target including the white region, representing light intensity of different portions of the target detected by the PDA during the first FET. White areas can be replaced by bright areas (or other highly reflective areas). For example, any area with a reflectance greater than 50% may be used instead. The black target can be replaced with a dark area (or other slightly reflective area). For example, any target having a reflectivity of less than 10% may be used instead.

Step 3720 includes processing the first frame information based on the first FET to provide a first image comprising a bright area surrounded by a dark background. Optionally, step 3720 may be implemented using any of the image generation processes discussed above with respect to any of steps 2406 , 2414 , and 2422 of method 2400 .

Step 3730 includes receiving, from the PDA, second frame information of the black target comprising a white region, representing light intensity of a different portion of the target detected by the PDA during a second FET longer than the first FET.

Step 3740 includes processing the second frame information based on the second FET to provide a second image comprising a dark background without bright areas. Optionally, step 3740 can be performed using any of the image creation processes discussed above with respect to steps 2406 , 2414 , 2422 of method 2400 and the previous step of identifying groups of usable and unusable PSs. can be implemented.

With respect to the execution order of the method 3700 , step 3720 is executed after step 3710 , and step 3740 is executed after step 3730 . In addition, any suitable order of steps may be used. Method 3700 may also optionally include capturing the first frame information and/or the second frame information via the PDA.

Optionally, the reception of the second frame information may be performed after receiving the first frame information and then determining a second FET that is longer than the first FET. Optionally, the processing of the second frame information discards the detected light intensity information of the white region based on the second FET, and in response to the detected light intensity of the adjacent region of the second frame information, at least one of the second image determining a dark color for the corresponding pixel. Optionally, processing the second frame information may include identifying, based on the second FET, at least one PS detecting light from the white region as unavailable for the second frame. Optionally, the first exposure value (EV) of the PDA during capturing the first frame information may be different from the second EV of the PDA during capturing the second frame information by less than 1%.

Optionally, dark current accumulation on the PS associated with the low reflectivity data during the first frame exposure time leaves a usable dynamic range for the PS, and the dark current accumulation on that PS during the second frame exposure time results in insufficient dynamic range for the PS. leave behind In this case, the PS corresponding to the high reflection region cannot be used for image generation in the second image, and an alternate color value can be calculated to replace the missing detection level.

A non-transitory computer readable medium is provided for generating image information based on data of a PDA, which, when executed on a processor, comprises the following steps: (a) of a different portion of a target detected by the PDA during a first FET receiving, from a PDA, first frame information of a black target including a white area indicating light intensity; (b) processing the first frame information based on the first FET to provide a first image comprising a bright region surrounded by a dark background; (c) receiving, from the PDA, second frame information of a black target comprising a white region, representing light intensity of a different portion of the target detected by the PDA during a second FET longer than the first FET; (d) processing the second frame information based on the second FET to provide a second image comprising a dark background without bright areas;

The non-transitory computer-readable medium of the preceding paragraph may include additional instructions that, when executed on a processor, perform any other steps or variations discussed above with respect to method 3700 .

In the above disclosure, a number of systems, methods, and computer code products are described, as well as methods of using them to electro-optically capture and generate high-quality images. In particular, these systems, methods, and computer code products may be utilized to generate high quality SWIR images (or other SWIR sensing data) in the presence of high PD dark currents. This PD may be a Ge PD, but not in all cases. While some methods of using such systems, methods, and computer program products in a synergistic manner have been discussed above, many other methods are possible and are considered part of the innovative invention of this disclosure. Any system discussed above may be used to achieve higher quality results, similar results in a more effective and cost effective manner, or for any other reason, any system from any one or more other systems discussed above. It may include one or more components. Likewise, any of the methods discussed above may be used to achieve a higher quality result, to achieve a similar result in a more effective and cost-effective manner, or for any other reason, from any one or more other methods discussed above. It may include any one or more steps.

In the paragraphs below, some non-limiting examples of such combinations are provided to demonstrate some of the possible synergies.

For example, imaging systems 100, 100' and 100", whose integration times are short enough to overcome the excessive effects of dark current noise, may use PDD 1300, 1300, PDDs such as 1300', 1600, 1600', 1700, 1800 can be implemented to be included in the receiver 110. In this way, the capacitance of the PS is not overwhelmed by the time-invariant portion of the dark current that is not accumulated in the detection signal. and the noise of the dark current does not obscure the detection signal. Implementing any PDD (1300, 1300', 1600, 1600', 1700, 1800) in any imaging system (100, 100' and 100") is meaningful. While still detecting the signal, it can be used to prolong the frame exposure time to an appreciable extent (since the DC portion of the dark current does not accumulate in the capacitance).

For example, imaging systems 100, 100' and 100" in which integration times are set short enough to overcome the undue effects of dark current noise may be implemented by implementing any one or more of methods 2400, 2500, and 3500, so that any PS determines whether a given frame exposure time is available, and allows the frame exposure time (corresponding to the integration time) to be reduced even further to further ensure that a sufficient number of PSs are available. The expected ratio between the dark current noise levels and the expected availability of different PSs in these FETs will depend on the controller to set the balance between the quality of the detected signal, the amount of pixels available, and the required illumination level from the light source (e.g., laser 600). The availability model in different FETs may also be used to determine the distance range of the gated images generated by imaging systems 100, 100' and 100", where applicable. The additional inclusion of any of the PDDs 1300, 1300', 1600, 1600', 1700, 1800 as sensors in these imaging systems would add to the advantages described in the previous paragraphs.

For example, any one or more methods 2400, 2500, and 3500 may be applied to system 1900 (or any EO system including any PDDs 1300, 1300', 1600, 1600', 1700, 1800). can be implemented by The reduction in dark current accumulation effects discussed with respect to system 1900 (or any PDD mentioned) allows the use of longer FETs. Determining a PS temporarily unavailable in a relatively long FET is such that system 1900 (or other EO system with one of the mentioned PDDs) discards that PS, and optionally replaces the detection output with data from the surrounding PS. Implementing any method can be used to facilitate longer possible FETs.

Some steps of the aforementioned method may also be embodied as a computer program for execution on a computer system, including at least code portions for performing the steps of the related method when executed on a programmable device such as a computer system. or, enable a programmable device to perform the functions of a device or system according to the present disclosure. Such a method may also be implemented as a computer program for execution on a computer system, comprising at least a portion of the code for causing a computer to execute the steps of the method according to the present disclosure.

A computer program is a list of instructions, such as a specific application program and/or operating system. A computer program may include, for example, subroutines, functions, procedures, methods, implementations, executable applications, applets, servlets, source code, code, shared libraries/dynamic load libraries and/or other sequences of instructions designed to be executed on a computer system. may include one or more of

The computer program may be internally stored in a non-transitory computer readable medium. All or part of the computer program may be provided on a computer readable medium permanently, removably or remotely coupled to the information processing system. Computer-readable media may include, for example, without limitation: magnetic storage media including disk and tape storage media; optical storage media such as compact disc media (eg, CD ROM, CD R, etc.) and digital video disc storage media; non-volatile memory storage media including semiconductor-based memory units such as flash memory, EEPROM, EPROM, and ROM; ferromagnetic digital memory; MRAM; Volatile storage media including registers, buffers or cache, main memory, RAM, etc.

A computer process typically includes an executing (running) program or part of a program, current program values and state information, and resources used by the operating system to manage the execution of the process. An operating system (OS) is software that manages a computer's resource sharing and provides programmers with an interface used to access these resources. The operating system responds by processing system data and user input, and allocating and managing tasks and internal system resources as services to users and programs on the system.

A computer system may include, for example, at least one processing unit, an associated memory, and a number of input/output (I/O) devices. When executing a computer program, the computer system processes the information according to the computer program and produces resultant output information via the I/O device.

The connection discussed herein may be any type of connection suitable for transmitting a signal to or from each node, unit or apparatus, for example, via an intermediate apparatus. Thus, unless implied or otherwise stated, a connection may be, for example, a direct connection or an indirect connection. A connection may be illustrated or described as being a single connection, a plurality of connections, a unidirectional connection, or a bidirectional connection. However, other embodiments may change the implementation of the connection. For example, a separate one-way connection can be used rather than a two-way connection, and vice versa. Also, multiple connections may be replaced with a single connection that transmits multiple signals serially or in a time multiplexed manner. Likewise, a single connection carrying multiple signals may be split into various other connections carrying subsets of these signals. Thus, there are many options for signal transmission.

Alternatively, the illustrated example may be implemented as a single integrated circuit or circuit located within the same device. Alternatively, the examples may be implemented as any number of separate integrated circuits or discrete devices interconnected in any suitable manner. Optionally, the appropriate portions of the method may be implemented as physical circuits or soft or code representations of logical representations convertible to physical circuits, such as in any suitable type of hardware description language.

Other modifications, changes, and alternatives are possible. Accordingly, the specifications and drawings are to be regarded in an illustrative rather than a restrictive sense. While certain features of the present disclosure have been illustrated and described herein, many modifications, substitutions, changes and equivalents will occur to those skilled in the art. Accordingly, it is to be understood that the appended claims are intended to cover all such modifications and variations that fall within the true spirit and scope of the present disclosure. The embodiments described above have been cited as examples, and it will be understood that various features thereof and combinations of these features may be changed and modified. While various embodiments have been shown and described, it is not intended to limit the invention by such disclosure, but rather to cover all modifications and alternative constructions falling within the scope of the invention, as defined by the appended claims. will understand

In the claims or specification of this application, unless otherwise stated, adjectives such as "substantially" and "about" that modify a condition or relational characteristic of a feature or features of an embodiment are relative to the application for which the condition or feature is intended. It is understood to mean defined as being within an acceptable tolerance for the operation of the embodiment. Where a claim or specification refers to “an” element, it is to be understood that such reference should not be construed as presenting only one of that element.

All patent applications, white papers and other publicly available data have been published by TriEye LTD, Tel Aviv, Israel, the assignee of the present disclosure, which is incorporated herein by reference in its entirety. Any reference mentioned herein is not admitted to be prior art.

Claims (12)

An active short-wave infrared (SWIR) imaging system comprising:
A pulsed illumination source operative to emit pulses of SWIR radiation towards a target, the pulses of radiation impinging upon the target to generate pulses of SWIR radiation reflected from the target;
an imaging receiver comprising a plurality of germanium (Ge) photodiodes (PD) operative to detect the reflected SWIR radiation, the imaging receiver, for each Ge PD, reflected SWIR radiation impinging on each Ge PD generate a dark current greater than 50 μA/cm², time-dependent dark current noise and time-independent read noise; and
a controller operative to control operation of the imaging receiver during an integration time during which accumulated dark current noise does not exceed the time-independent read noise, the operation triggering the initiation of continuous signal acquisition by the imaging receiver, triggering As a result of, for each Ge PD, collect the charge resulting from the impact of the reflected SWIR radiation on at least each Ge PD, and the amount of charge collected as a result of dark current noise is collected as a result of time-independent read noise. trigger the cessation of charge collection when it is still lower than the charged amount;
An active short-wave infrared (SWIR) imaging system comprising a. 2. The active SWIR imaging system of claim 1, further comprising a readout circuit for reading the charge accumulation collected by each Ge PD to provide a respective detection signal after the integration time. 3. The imaging receiver according to claim 1 or 2, wherein the imaging receiver outputs a respective set of detection signals representing the charge accumulated by each of the plurality of Ge PDs during an integration time, wherein the set of detection signals comprises at least one SWIR radiation pulse. An active SWIR imaging system representing an image of a target illuminated by 3. An active SWIR imaging system according to claim 1 or 2, comprising at least one diffractive optical element (DOE) operative to improve the illumination uniformity of the light of the pulsed illumination source prior to emitting the light. 3. The method according to claim 1 or 2, wherein the controller is operative to operate the imaging receiver to sequentially acquire a series of gated images, each of the gated images being a respective one of a different Ge PD at a different distance range. wherein the active SWIR imaging system further comprises an image processor operative to combine a series of images into a single two-dimensional image. 3. The active SWIR imaging system of claim 1 or 2, wherein the active SWIR imaging system is an uncooled Ge-based SWIR imaging system operable to detect a 1 m x 1 m target with a SWIR reflectivity of 20% at a distance of 50 m or greater. A method for generating a shortwave infrared (SWIR) image of an object in the field of view (FOV) of an electro-optical system, comprising:
emitting at least one illumination pulse toward the FOV to generate reflected SWIR radiation from the at least one target;
triggering initiation of continuous signal acquisition by an imaging receiver comprising a plurality of germanium (Ge) photodiodes (PD) operative to detect the reflected SWIR radiation;
As a result of triggering, for each Ge PD, at least the charge arising from the collision of the SWIR reflected radiation for each Ge PD, dark current greater than 50 μA/cm², integration-time dependent dark current noise and integration-time independent read noise. collecting;
triggering cessation of charge collection when the amount of charge collected as a result of the dark current noise is still lower than the amount of charge collected as a result of the integration-time independent read noise; and
generating an image of the FOV based on the charge level collected by each Ge PD;
How to include. 8. The method according to claim 7, wherein, after cessation of the collection, a signal correlated with the amount of charge collected by each Ge PD is read by a readout circuit, the readout signal is amplified, and the amplified signal is provided to the image processor to How to do image creation. The method according to claim 7 or 8, wherein the signal output by each Ge PD is a scalar value representing the amount of light reflected from 20m, the amount of light reflected from 40m and the amount of light reflected from 60m. 9. The method of claim 7 or 8, wherein generating the image comprises generating an image based on a scalar value read for each Ge PD. 9. The method according to claim 7 or 8,
repeating the sequence of emitting, triggering, acquiring and stopping multiple times;
triggering the acquisition at a different time than the emission of light in every sequence; and
reading from the imaging receiver a detection value for each Ge PD corresponding to a different distance range wider than 2 m;
further comprising,
wherein generating the image comprises generating a single two-dimensional image based on detection values read from different Ge PDs in different sequences. 9. The method according to claim 7 or 8,
performing the acquisition when the imaging receiver operates at a temperature of 30° C. or higher; and
processing the image of the FOV to detect a plurality of vehicles and a plurality of pedestrians in a plurality of ranges between 50m and 150m;
How to further include

Images